@@TommyBo42 Not "but it approaches infinity". Instead, "something" approaches infinity. That something is actually "something else" ppl dont understand unless they have knowledge of math analysis.
@@TommyBo42 no if f(x)=1/x .. as x increases or approaches infinity f(x) gets smaller ..if x goes towads zero f(x) increases .. but f(x)is Undefined for x=0 ..it makes as much sense as take the Inverse sine of 2 wich is undefined
I'm glad to see that a lot of people didn't go through the entire process, and rather know or have come to the conclusion that in order to double the percentage of right-handed people, you need to halve the total number.
Hello. I've only began to pursue math recently after a long break since the end of school. This problem did not come intuitively at all for me, do you have anything you would recommend beside doing more of these, or is it just a natural talent I don't have?
@@TroySturges-g6u make excel spreadsheets about video games with respect to crit chance, crit damage, attack speed, damage mitigation, effective total health etc. You'll get intuitive about percentages real quick
That is going through the entire process, only very quickly. When you solve in your head, you go through all the steps, just without spending so much time writing.
I thought about it like this. At the beginning there is one right-handed person in the room. How many left-handed people do I need for there to be 2% right-handed people in the room? Clearly I need 49. Therefore I have to remove 50 left-handed people. I did all this in about 5 seconds.
yeah, it's easiest and fastest to turn the percentage of right-handed people into a ratio to all people in the room. I thought about it about the same: 1% is 1:100, and then 2% is 2:100, or 1:50. to get from 1:100 to 1:50, you take away 50 left-handed people.
I realized immediately that just removing a person would result in a non-integer percentage, but it took me a while to realize what else to do. But I'm proud to say I got the answer before he said it!!!
ya, took a min realise what was asked... but its easier calculate on those right handed u want right handed to be 2% ot the total left in the room -> 1/.02=50 ppl must be left in the room ..would had been fun if thay asked how many have to leave to bring it down to 97%
That is a superb analysis from you there. The quiz show that this question is from i was watching when aired, i was furious that i got it wrong, but your lesson there im gunna remember for future maths questions.
I thought about it like this: When you want 100 people with 98% left handed, you need 98 left handed and 2 right handed people. Then I divided both by two so there’s only one right handed person. That left me with 49 left handed people. And 99-49=50, so 50 left handed people have to leave.
@@TrentRProductions Lol, I was reading the comments while assuming the video gave the quick solution. But now I took a look at the video and it is truly horrible, lol.
I calculated it using some algebra. The original percentage of 99% is 99 left-handed people out of 100 people in total. If we represent the number of left-handed people that will leave the room with “x”, then we have (99 - x)/(100 - x) = 98% (the new percentage we are looking for) = 0.98. Once you work it out, you get x = 50.
@@ronald3836now tell me how many people need to leave for the percentage to be below 93.5%. You can’t do that just by looking at it but the formula still holds up. Maybe think for a second why what he is doing might be important
This is the first one on your videos that I figured out immediately. My brain went to one person is 1% in the initial scenario, so for someone to be 2% of the group there would need to be half the total people.
Go in the opposite direction: start with 1 right-handed person. How many lefties do you need to bring in to the room to get to a ratio of 100:2 (given that the max number of righties is 1)?
The Percentile quantities were Supposed to Confuse the Reader, as some commenters STATED, it's Best to make a Formal Computation rather than Follow a Seemingly Logical answer...😊😎👍
I used my own method, my 26 years of experience of math, my very own logic and solve it by only 5 seconds by just jumping the video at the end and got 50 as an answer
@@JuergenW. the concept of the original show is the questions get harder based on how many people are able to answer them, and the final question is supposed to be answerable only by 1% of people. They have a panel of 100 people answering the questions along with the contestant and you see how many of them go out on each question. Of course, it doesn't mean the same 1% will be able to answer all of the 1% questions on the show. Some, like this one, I find quite easy. Others are more complicated.
Quick intuitive approach - equation balancing, you want to double the number of right handed people, inversely, you need to half the number of left handed.
You need to halve the total number of people in the room! Your stated approach 99/2=49.5 is a bit brutal and doesn't solve the problem! ( Not questioning your reasoning, you didn't word it right! )
@alexandergutfeldt1144 correct, I didn't want to write an essay. I left out the parts of keeping the total number of people at 100 by converting the lefts to rights, reducing by the desired ratio (accidental time stamp), then converting back with the new group. Thanks for keeping me honest, I lazy math often.
@@alexandergutfeldt1144 are you stoo-pid ?? He clearly wrote "quick INTUITIVE approach" He didn't write "correct calculation" Do you ever get invited to social events?
Took me ages to realize if people leave there would no longer be 100 people... Once this was clear, answer became obvious. In a TV show I would have panicked.
I used a slightly different method. 99 are left handed so that means 1 is right handed. 1 out of 100 equals 1% 1 out of 50 total equals 2%. That means 50 less Total people.
Another problem is asking how to bring the percentage down to 96%. The answer is 75 left-handed people must leave the room leaving 1 right-handed person and 24 left-handed people. 24 out of 25 is 96%. The easier way to calculate this is to concentrate on the number of right-handed persons which is always one. 1=4x/100 which equals 25 so there are 24 left-handed and 1 right-handed so 75 of 99 left-handed must leave the room. In the problem given the equation would be 1=2x/100 which equals 50 so there is 1 right-handed and 49 left-handed (49 out of 50 is 98%) so 50 left-handed must leave the room. This math is easier than what is shown.
apparently I'm the only person who thought this was a rounding problem and said 35 people need to leave, because 65/66 = 0.984 which rounds down to 98%
Because it's not a rounding problem and you can have percentages with decimal places in them, such as 98.4% with no requirement to round them into a whole number. By assuming that you should round the percentages, you are essentially making up your own question rather than solving the question that was actually asked.
50 people, 99/100 is 99% 49/50 is 98% Kevin of Vsauce2 covered this exact thing albeit with a different premise (something to do with potatoes iirc). You can also look at it the other way round, there is 1 right handed person 1 out of 100 is 1% you need it to be 2% so 1/0.02 (or 100/2) which is 1 out of 50
As others have pointed out, I solved it by thinking how many people in total they had to be for one person to equal 2%, which is one out of fifty (so 49 others). Thus simply 99-50 = 49. But I appreciate the more algebraic solution to the general problem, where the numbers might be harder to think about in your head.
@@utopiandystopia1383 you do realize that ChatGPT and AI are not the same thing, right. ChatGPT is just one instance of general knowledge AI that is more of a gimmick to introduce AI to layman society and make hype for it than a really functional AI. We already have loads of much better AI models for specialized tasks. I would love to see a game with fully AI based npc responses. For people that don't have many friends or just have hard time to gather them at the same place and the same time, it would as close as they can get to a true RPG session 😁
the easiest way to figure it out is to put the question on the reverse: how many left-handed persons need to leave the room to have the right handed guy representing 2% of the total. and now the answer is evident: 50.
I solved it mentally with algebra. The hardest part was remembering the numbers, keeping them in mind. Here ‘s the equation: 99-x/ 100-x = 98/100. It took me more than 30 seconds to do it, though. Still, not bad for an octogenarian!
Easier mathematical manipulation if you recast as right-handed percentage. 1 right-handed person in the room with 99 left-handed is 99% left handed or 1% right handed. So to go down to 98%-left is to go up to 2%-right. Equation is almost the same but much quicker to solve since there is always 1 right handed peron and "x" left-handed people need to leave ther room 1/(100-x) = 0.02 Note it is easier if you recall that 0.02 = 2/100 = 1/50 1/(100-x) = 1/50 So 100-x = 50. x=50
Like I mean if the question went Like this In a room of 100 people, 99% are left-handed. How many left-handed people have to leave the room to bring that percentage down to 97%?
@@kingellsgaming Not without cutting people in pieces. 3/100 equals 1 out of 33 1/3. So impossible 66 2/3 persons leaves the room. I don´t like that so let us take 96% as an new example. 4% rigthhanded is one out of 25. 75 lefthanded have to leave the room. I think you got it.
Because we are dealing with strictly whole numbers here, there are only a two ways a group of 100 or less can contain a subgroup comprising EXACTLY 98%. Namely, 98/100 or 49/50. The first is precluded since we start with 99/100 and we can't get to 98/100 by removing. So the second is the only outcome that fills the requirement: the number of lefties must go down by 50, leaving the original righty.
to try to solve it within 30 seconds a viable option is 98% = 98/100 reduce this fraction 49/50 luckily the original condition was 99/100 = 99% so removing 50 from numerator and denominator (removing 50 left handed people removes 50 from total) leads to 98% looking at the comments, the 1% to 2% trick is even better (thinking of the complement, amount of right handed people) 1/100 2/100 = 1/50 (so removing 50 from 100) either way, final ans 50.
Similar effect is seen in video games with damage and damage reduction values. 100 damage while having 90% reduction is 10 damage. Getting just 5% more to 95% reduction halves the incoming damage to 5.
Its pretty easy to solve in your head once you stop thinking about left handed people and start thinking of the single right handed person. Not sure if it took me more or less than 30 seconds, but somewhere in that general range.
I still haven't watched the video nor read the comments, this is how I did it: 98% = (99-x)/(100-x), which yields x = 50. My explanation for the equation is the following. "99-x" is the final number of left-handed people in the room, x is the number of lefties who left (pun intended. Laugh!). The denominator will simply be the total number of of people in the room, which is one more than "99-x", so "100-x". Now, simply equals that with 98% and solve for x. By the way, the addition of one more comes about because there is a right-handed, airhead strolling about this weird left-handed people congress. Edit: yep! 👍🏻
If this were a question from a TV show, the participant likely would not have had enough time to solve the equation as Steve demonstrated. Perhaps we can think of it this way: The percentage calculation in the question is always in the form of (x-1)/x, where x is the total number of people left in the room. The required percentage, 98%, can be expressed as 98/100=49/50, which matches the form (50−1)/50.
50. Basically the single right handed person is 1/100. For it to become 2/100 = 1/50, the number of left handed must decrease to 50-1=49. So from 99 to 49 is 50 left handed people must leave.
04:47 It would be easier to calculate this, if we would firstly multiply both sides by 100 (to get 100=2*x), and secondly divide both sides by 2 (to get 100/2 = x and x=50).
I read the thumbnail and immediately started guessing n/(n+1) values until I found the answer, then I started the video. The algebraic method and logic makes a lot of sense!
I'm 43 years old and this is the first time i've seen a useful implementation of something that i forgot in the last millenium. But the fact, that one person equals 2% in 50 people was just an intuitive thought at start of the video 😅
Another intuitive way to think of this is to change the side you're looking at. If only 1% are right handed, we need to get that to 2% in order to reduce the left handed side to 98%. We can't double the number of right handed people to reach that target since we're only allowed to remove people, so we have to reduce the number of left handed people by 50%
I am sorry..I zoned out halfway through the proces and thought about if I could get the football court in recess before the other classes... just like 27 years ago when I was in math class....
Originally heard this question with very watery potatoes. (If a potato is 99% water by weight, what percentage of the weight would you need to dehydrate in order to make it 98% water)
What’s crazier is in order to get down to 97%, you’d have to remove sixteen and two thirds more left-handers from the room. To get down to 96%, you’d then have to remove eight and a third more left-handers. To decrease by 1% each time, the total people who STAY in the room must go from 100 to 50 to 33.33 to 25 to 20 to 16.66 to 14.285714 etc. Notice this follows the pattern of denominators 1/1, 1/2, 1/3, 1/4, 1/5, 1/6, 1/7 etc. The number of people who need to LEAVE the room goes from 50 to 16.66 to 8.33 to 5 to 3.33 to 2.380952 to 1.7857142 etc. which follows a different pattern of denominators 1/(1x2), 1/(2x3), 1/(3x4), 1/(4x5), 1/(5x6), 1/(6x7) etc.
This math problem and solution actually makes you think about whether statistics actually reflect on social issues when a 1% drop in any social measurements may result in no actions whatsoever...i havent been able to rationalise the rest yet somebody help
Last time I saw that question, it was about a watermelon weighing 100 pounds that was 99% water and the question was how much water would have to evaporate from it for it to be 98% water.
In order for ONE right handed person to represent 2% of the total they have to be the only one out of 50 1/50 = 0.02 = 2%. One for every 50 equals two for every hundred in percentgage terms that means the room has to lose a total of 50 left-handed people.
My way of solution was, in the first case for 1 right-handed there are 99 left-handed. How many of left-handed has to leave so the ratio change to 1 right-handed to 49 left-handed (2-98). And you see the answer immediately. Interesting question though.
I thought about like this. Basically, if you remove one person, that's -1 for both the total and the number of left handed, which isn't exactly 98% in any case instead of 49 people out of 50 total people. And 99 - 49 is 50 people
Nice seeing it all done out thoroughly. My thought process just went "if we only have 1 righty, what number is one 2% of? Yep, 50, get rid of 50 lefties".
A simpler way to do this is to think of it from the right hand persons perspective, since the people we remove are only left handed, the 1 right handed person is constant, and therefore the percentage value they hold can help in calculating the rest, 1 is currently 1% of the total number of people, and since we need left handed people to become 98%, the remaining 2 % is the 1 Right handed person. So 1 went from being 1% of 100 to 2% of x. From there, it's straight forward. x*2/100=1. x=100/2=50. so the total number of people remaining in the room is 50, subtract that from the original number and you have the number of people that needs to be removed in order to match the required percentages.
I would think that to go from 1% Right handed to 2% right handed, you would need to half the total number of people, so 50 would need to leave the room so that 1 person equates to 2% of people.
I actually managed to do this as well after thinking about it for about 5 minutes and here’s my formula for this: x/x+1 * 100 = 98% Where x is the number of people left when there are 98% of people are left handed and the x+1 ensures that there is still one person who isn’t left handed With a bit of algebra you’ll get x = 49 Subtract this from 99 and your answer is 50 👏
The way I thought about this was simply what is the number of people at which 1 person represents 2% of the total number of people. 50 people total, 49 of whom are left-handed. Remove 50 from the original room to get there.
also you can think of it as 1 person being equal to 1% in the beginning and at the end each person is worth 2% of the total. so you can put it in an equation where the left handed have to equal 98% and the right handed being 2% meaning that there can only be a difference of 1 person between the two groups and the only way to get to 100 this way is with 49 and 50
without knowing the answer, by intuition it seems something similar like the old joke "A bat and a ball cost $1.10 in total... " it depends on how it is formulated and that's why most of people fall into the trap
I managed to figure this on TV as I was playing along after about 25 seconds and I was really proud of myself. I just converted it to a ratio in my head and recognise the 49:1 was the only way to get to 98% with one left hander. The one percent club is a great show, it really tests your problem solving and honestly I have more fun playing along than any other quiz show.
a simpler way of thinking about this is if I have 1 right handed person in a room, how many left handed people need to be in the room for right handed person to make up 2 percent of it
only 1 lefthanded person has to leave the room... the catch is that a righthanded person has to enter, but the question never stated you cant add righthanded individuals to the room
Yes, or even simply add 48 left-handed people and 2 right-handed. That way you don't need to remove any left-handers and the answer to the question is 0.
You need to state the problem more precisely. As "exactly 98%", because a normal understanding is to make the fraction less than 0.985, because percentages without a decimal point are all rounded.
98% is precise. It is precisely equal to "exactly" 98%. This is like saying that he needs to state that there are "exactly 100" people in the room or that "exactly 99%" of them are left-handed. The problem never stated nor implied that any of the values were rounded or approximations, nor does it ask for a rounded or approximated answer. It asks specifically for 98%
@@TrueThanny That's exactly how language works. If you accept that "100 people" is "exactly 100 people" then you have to also accept that "99%" is "exactly 99%" and that "98%" is "exactly 98%". You cannot say that one requires "exactly" to be specified but another does not. Either they're all precise or none of them are.
@@phiefer3 Man, you are terrible at analogies. It is beyond the comprehension of any sane, rational being how you think using _people_ as an example serves your argument. People cannot be fractional. Percentages are _always_ fractional. I'd suggest trying again, but it's really better that you don't. Your hole is only growing, and it would be irresponsible to give you any advice beyond dropping that shovel.
None have to leave if more can enter the room. For instance 50 people of which exactly 48 are left-handed. If no one may enter it's still none, but you might have to amputate.
The first thing to do is just go the brute force route and see what % will be at some nice number that you can easily multiply into 100. Like 50, which just turns out to be the answer. Or you can understand that you have 1% and need 2%, thus you need twice more, which means that you need to divide the total by two without decreasing your 1%, thus you need 50 left-handed people to leave.
My first knee jerk reaction was 1, then I thought and realized that the ratio wouldn't change hardly at all if you did that, so I thought you needed to reduce the number by a substantial amount to increase it to 2%. The next obvious choice for that is to think about what number would keep the ratio closest to 100% and let 1 be a small percentage of the number. Obviously 50, being a round half of 100 makes sense to go to, so you divide 50 by 1 and you get 2%. Using logic to worm your way out of having to do complex equations is fun lol.
For me, the best mental method would be to think of the right handed (1) and put it as a constante, so to have 98% of left handed it means that 2% = 1, 100% = 2*50% => 2*x=98 => x=49 Then u know the total ammount of left handed guy and the original ammount so its easy
1 ÷ 0 = 0? (a 3rd grade teacher & principal both got it wrong), Reddit r/NoStupidQuestions
th-cam.com/video/WI_qPBQhJSM/w-d-xo.html
Undefined, but it approaches infinity. So, 0 is about as wrong an answer as you can get.
@@TommyBo42 Not "but it approaches infinity".
Instead, "something" approaches infinity.
That something is actually "something else" ppl dont understand unless they have knowledge of math analysis.
@@TommyBo42 no
if f(x)=1/x .. as x increases or approaches infinity f(x) gets smaller
..if x goes towads zero f(x) increases
.. but f(x)is Undefined for x=0
..it makes as much sense as take the Inverse sine of 2 wich is undefined
Hence, my answer that it is undefined, but it approaches infinity as x gets closer to zero :) Cheers!
初探討極限理論? 相當嗨~
其實學好一點數學, 也沒什麼.
I'm glad to see that a lot of people didn't go through the entire process, and rather know or have come to the conclusion that in order to double the percentage of right-handed people, you need to halve the total number.
Hello. I've only began to pursue math recently after a long break since the end of school. This problem did not come intuitively at all for me, do you have anything you would recommend beside doing more of these, or is it just a natural talent I don't have?
@@TroySturges-g6u make excel spreadsheets about video games with respect to crit chance, crit damage, attack speed, damage mitigation, effective total health etc. You'll get intuitive about percentages real quick
@deesire thank you for your reply, I will give it a go!
That is going through the entire process, only very quickly. When you solve in your head, you go through all the steps, just without spending so much time writing.
Yeah, but if the numbers are awkward, you gotta know the math.
I thought about it like this. At the beginning there is one right-handed person in the room. How many left-handed people do I need for there to be 2% right-handed people in the room? Clearly I need 49. Therefore I have to remove 50 left-handed people. I did all this in about 5 seconds.
yeah, it's easiest and fastest to turn the percentage of right-handed people into a ratio to all people in the room. I thought about it about the same: 1% is 1:100, and then 2% is 2:100, or 1:50. to get from 1:100 to 1:50, you take away 50 left-handed people.
yeah, this is the obvious way to do it and shows that logic beats algebra in speed
@@eventhorizon853speed is not the reason you use algebra. It’s because of its reliability and verifiability.
Yeah very clickbait
yes
50 people. That stumped me for a hot minute before i realized what happens when you remove a person.
The bouncer will have had a full day!
I knew it wasn't 1 person but I didn't expect 50 .😂
But 49/50 will get you 98%.
I realized immediately that just removing a person would result in a non-integer percentage, but it took me a while to realize what else to do. But I'm proud to say I got the answer before he said it!!!
ya, took a min realise what was asked...
but its easier calculate on those right handed
u want right handed to be 2% ot the total left in the room ->
1/.02=50 ppl must be left in the room
..would had been fun if thay asked how many have to leave to bring it down to 97%
From memory: _this is one of those where it's about half isn't it?_
The small change from 99 to 98 obscures the large relative change from 1 to 2. This is a good general lesson.
That is a superb analysis from you there.
The quiz show that this question is from i was watching when aired, i was furious that i got it wrong, but your lesson there im gunna remember for future maths questions.
I thought about it like this:
When you want 100 people with 98% left handed, you need 98 left handed and 2 right handed people.
Then I divided both by two so there’s only one right handed person. That left me with 49 left handed people.
And 99-49=50, so 50 left handed people have to leave.
Yes! And this is so much easier
@@TrentRProductions Lol, I was reading the comments while assuming the video gave the quick solution. But now I took a look at the video and it is truly horrible, lol.
That's clever
I calculated it using some algebra. The original percentage of 99% is 99 left-handed people out of 100 people in total.
If we represent the number of left-handed people that will leave the room with “x”, then we have (99 - x)/(100 - x) = 98% (the new percentage we are looking for) = 0.98.
Once you work it out, you get x = 50.
@@ronald3836now tell me how many people need to leave for the percentage to be below 93.5%. You can’t do that just by looking at it but the formula still holds up. Maybe think for a second why what he is doing might be important
The multi marker skills are impressive
Yes, I noticed that in another of his videos.
How many markers can he multiplex ...maybe 5 ? :)
he is a true master of the ancient Black Pen Red Pen Technique 🖍️
@@LonkinPork 2 pens, 1 guy
@@Not.Your.Business reminds me of 1 cup 2....
This is the first one on your videos that I figured out immediately. My brain went to one person is 1% in the initial scenario, so for someone to be 2% of the group there would need to be half the total people.
That's a brilliant way of thinking about it.
Me too. I'm much too lazy to do the math when there is an easier way to come up with the answer.
That’s how I did it as well.
Go in the opposite direction: start with 1 right-handed person. How many lefties do you need to bring in to the room to get to a ratio of 100:2 (given that the max number of righties is 1)?
No need to guess. Just reason how many people you need to have the sole right-handed person represent 2%.
2% means 1 out of 50. That's all.
Yup, question only said remove left handed not add right handed
Percentage = x/ (x+1), set percentage to 98/100 which is = to 49/50=x/(x+1), x ist equal to 49. So 50 left handed ppl had to leave since 99-50 is 49
I couldnt remember the percentage formulas so couldnt do it in the time alloted, 40 years ago maybe
I found it easier leaving the percentage as a fraction:
(99-x)/(100-x) = 98/100
100(99-x) = 98(100-x) (distribute denominators)
9900 - 100x = 9800 - 98x
98x - 100x = 9800 - 9900
-2x = -100
x = 50
don't even need all that. 2% is 1/50th of total. so 50 people need to leave
@@bytemeahyou DO need all that to work it out in a formal and logical fashion that others can follow and learn from. Shortcuts don’t do that.
Man thanks so much
It is much easier 🎉🎉
The Percentile quantities were Supposed to Confuse the Reader, as some commenters STATED, it's Best to make a Formal Computation rather than Follow a Seemingly Logical answer...😊😎👍
Much easier to understand
I used my own method, my 26 years of experience of math, my very own logic and solve it by only 5 seconds by just jumping the video at the end and got 50 as an answer
It feels good to be a part of that 1% club
The club of 1% righthanded people in the room?!?
@@JuergenW. the concept of the original show is the questions get harder based on how many people are able to answer them, and the final question is supposed to be answerable only by 1% of people. They have a panel of 100 people answering the questions along with the contestant and you see how many of them go out on each question.
Of course, it doesn't mean the same 1% will be able to answer all of the 1% questions on the show. Some, like this one, I find quite easy. Others are more complicated.
The gameshow gives you 30 seconds to solve, took me about 15 when I realized 98/99 is still pretty close to 99%... and a short jump to 49/50 is 98%.
50. Had to pull out a calculator and guess-and-check. Never would have been able to figure that out on the spot on a gameshow.
Yeah with a lot of money riding on the answer - no pressure!
Had to quickly do it in my head. So, I'm pretty sure I would have got it.
Thanks for the Christmas gift of allowing us to momentarily feel smart.
Quick intuitive approach - equation balancing, you want to double the number of right handed people, inversely, you need to half the number of left handed.
You need to halve the total number of people in the room! Your stated approach 99/2=49.5 is a bit brutal and doesn't solve the problem!
( Not questioning your reasoning, you didn't word it right! )
@alexandergutfeldt1144 correct, I didn't want to write an essay. I left out the parts of keeping the total number of people at 100 by converting the lefts to rights, reducing by the desired ratio (accidental time stamp), then converting back with the new group. Thanks for keeping me honest, I lazy math often.
@@alexandergutfeldt1144 are you stoo-pid ??
He clearly wrote "quick INTUITIVE approach"
He didn't write "correct calculation"
Do you ever get invited to social events?
Took me ages to realize if people leave there would no longer be 100 people... Once this was clear, answer became obvious.
In a TV show I would have panicked.
I used a slightly different method.
99 are left handed so that means 1 is right handed. 1 out of 100 equals 1%
1 out of 50 total equals 2%. That means 50 less Total people.
Wow that’s really smart. I feel like that observation is the fastest method possible.
we use the same method what a coincidence
Did you use it before or after you got the answer? 😊
@@davidpereira4455 that's how I got the answer.
In chemistry, if you want to double concentration - you should somehow halve mass or volume. 😉
Same thing indeed.
Another problem is asking how to bring the percentage down to 96%. The answer is 75 left-handed people must leave the room leaving 1 right-handed person and 24 left-handed people. 24 out of 25 is 96%. The easier way to calculate this is to concentrate on the number of right-handed persons which is always one. 1=4x/100 which equals 25 so there are 24 left-handed and 1 right-handed so 75 of 99 left-handed must leave the room. In the problem given the equation would be 1=2x/100 which equals 50 so there is 1 right-handed and 49 left-handed (49 out of 50 is 98%) so 50 left-handed must leave the room. This math is easier than what is shown.
This is one of those problems that I'd get right instantly and lose credit for not showing my work
5:00 fifty!
This assumes you don't remove the one right-handed person! Then, it suddenly becomes (and remains) 100% left-handed.
@@jamesharmon4994
The original problem says ‘how many left-handed people have to leave the room’.
@jamesharmon4994 the questions specifies left handers
Instead of leaving the room just make them ambidextrous and then slowly phase out their left hand
@Kerguelen.Mapping Then... you just have to do it to ONE person.
apparently I'm the only person who thought this was a rounding problem and said 35 people need to leave, because 65/66 = 0.984 which rounds down to 98%
Because it's not a rounding problem and you can have percentages with decimal places in them, such as 98.4% with no requirement to round them into a whole number. By assuming that you should round the percentages, you are essentially making up your own question rather than solving the question that was actually asked.
50 people, 99/100 is 99% 49/50 is 98% Kevin of Vsauce2 covered this exact thing albeit with a different premise (something to do with potatoes iirc). You can also look at it the other way round, there is 1 right handed person 1 out of 100 is 1% you need it to be 2% so 1/0.02 (or 100/2) which is 1 out of 50
As others have pointed out, I solved it by thinking how many people in total they had to be for one person to equal 2%, which is one out of fifty (so 49 others). Thus simply 99-50 = 49. But I appreciate the more algebraic solution to the general problem, where the numbers might be harder to think about in your head.
Out of interest I asked ChatGPT and it told me the answer was 1, the right-handed person had to leave the room lol
Chat gpt o1 respondeu corretamente.
Thats chat gpt for you, cant even do what computers are supposed to be good at 🤣 i cant belive people want that thing to be npc dialogue for games
I asked chat Gpt and it gave the correct answer with calculations
@@utopiandystopia1383Maybe you are not using Gpt 4o I tried it multiple times and it gave the right answer
@@utopiandystopia1383 you do realize that ChatGPT and AI are not the same thing, right. ChatGPT is just one instance of general knowledge AI that is more of a gimmick to introduce AI to layman society and make hype for it than a really functional AI. We already have loads of much better AI models for specialized tasks. I would love to see a game with fully AI based npc responses. For people that don't have many friends or just have hard time to gather them at the same place and the same time, it would as close as they can get to a true RPG session 😁
49/50=98%, as long as that one right-handed person isn't one of the persons that leaves the room.
Bro how lucky am I to search this and only your video came up that was uploaded 5hr ago. Nice
If one of the people who leaves happens to be the right handed one, then you'd have 100% left handers.
50. It’s a simple equation (99-x)/(100-x) = 0.98 . Which simplifies to 0.02x = 1 and hence x=50
I was given a similar question years ago in high school, and yeah, it stumped me. However, that's one of those things that only gets you once!
This is a great question to ask LLMs. They have lots of trouble with it...
Nah they solve it without problem
Before we can solve this problem, we need to prevent the right handed person from escaping.
Let us assume that x people have to leave.
So, if 99/100 x 100 = 99%, then
100(99-x)/100-x = 98%
9900 - 100x = 9800 - 98x
100 = 2x
50 = x
U're wrong
Easier to look at the number who can stay. 2% means 1 in 50. So 50 stay, therefore 50 leave.
@@kotbegemot9177It'd be more helpful if u explain what's wrong instead of just saying it
@@ronald3836I wrote as how you would write in an exam or if you are bad with mental calculations
@@leaDR356 i mean that, "98%" should be "0,98" in your calculation, equation
I love your videos! I’m terrible at math, yet I find so many elements about it (like this) so truly fascinating.
I solved it in 10 seconds:
If they are 100 people every person is 1%, half of those and every person equals 2% so they need to be 49 out of 50.
Same here, same reasoning, about the same time!!
Yep, but you didn’t prove it. That’s what this video is about. Finding the solution is not hard at all. Proving it is something else. Gratz though 🎉
I solved in too in a couple of seconds! I skipped the video to the end :-D
the easiest way to figure it out is to put the question on the reverse: how many left-handed persons need to leave the room to have the right handed guy representing 2% of the total. and now the answer is evident: 50.
I solved it mentally with algebra. The hardest part was remembering the numbers, keeping them in mind. Here ‘s the equation: 99-x/ 100-x = 98/100. It took me more than 30 seconds to do it, though. Still, not bad for an octogenarian!
It’s easier to guess if you think that you need the right handed to be 2%, then you realize that you need half the people straight away
Easier mathematical manipulation if you recast as right-handed percentage. 1 right-handed person in the room with 99 left-handed is 99% left handed or 1% right handed. So to go down to 98%-left is to go up to 2%-right. Equation is almost the same but much quicker to solve since there is always 1 right handed peron and "x" left-handed people need to leave ther room
1/(100-x) = 0.02 Note it is easier if you recall that 0.02 = 2/100 = 1/50
1/(100-x) = 1/50 So 100-x = 50. x=50
Thinking through the solution in my head my own way seems so much easier than the presented equation
99 out of 100 (initial)
98 out of 100 (final)
Final one can be written as 49 out of 50 tooo so basically u took out 50 people.
one of the few questions that i could actually solve! and its so satisfying to be able to solve a math question on your own without help, love it!
Only one person right handed. 2% right-handed = 1/50 so 50 left-handed have to leave the room.
Exactly.
How did u get 2% please I'm so confused. Help me
Wait I got how u got that now so is it also applicable if what I need to remove is 3%?
Like I mean if the question went Like this
In a room of 100 people, 99% are left-handed. How many left-handed people have to leave the room to bring that percentage down to 97%?
@@kingellsgaming Not without cutting people in pieces. 3/100 equals 1 out of
33 1/3. So impossible 66 2/3 persons leaves the room. I don´t like that so let us take 96% as an new example. 4% rigthhanded is one out of 25. 75 lefthanded have to leave the room. I think you got it.
Because we are dealing with strictly whole numbers here, there are only a two ways a group of 100 or less can contain a subgroup comprising EXACTLY 98%. Namely, 98/100 or 49/50. The first is precluded since we start with 99/100 and we can't get to 98/100 by removing. So the second is the only outcome that fills the requirement: the number of lefties must go down by 50, leaving the original righty.
to try to solve it within 30 seconds
a viable option is
98% = 98/100
reduce this fraction
49/50
luckily the original condition was 99/100 = 99%
so removing 50 from numerator and denominator (removing 50 left handed people removes 50 from total)
leads to 98%
looking at the comments, the 1% to 2% trick is even better (thinking of the complement, amount of right handed people)
1/100
2/100 = 1/50 (so removing 50 from 100)
either way, final ans 50.
I like your method, too.
Similar effect is seen in video games with damage and damage reduction values. 100 damage while having 90% reduction is 10 damage. Getting just 5% more to 95% reduction halves the incoming damage to 5.
my dumb ass said 2
Its pretty easy to solve in your head once you stop thinking about left handed people and start thinking of the single right handed person. Not sure if it took me more or less than 30 seconds, but somewhere in that general range.
I still haven't watched the video nor read the comments, this is how I did it:
98% = (99-x)/(100-x), which yields x = 50.
My explanation for the equation is the following. "99-x" is the final number of left-handed people in the room, x is the number of lefties who left (pun intended. Laugh!). The denominator will simply be the total number of of people in the room, which is one more than "99-x", so "100-x". Now, simply equals that with 98% and solve for x.
By the way, the addition of one more comes about because there is a right-handed, airhead strolling about this weird left-handed people congress.
Edit: yep! 👍🏻
If this were a question from a TV show, the participant likely would not have had enough time to solve the equation as Steve demonstrated. Perhaps we can think of it this way:
The percentage calculation in the question is always in the form of (x-1)/x, where x is the total number of people left in the room. The required percentage, 98%, can be expressed as 98/100=49/50, which matches the form (50−1)/50.
I figured it'd be an easy enough question to do without calculator or pen and paper, so I simplified 98/100 and got the answer pretty quickly.
This is one of those things that is obvious once you know the answer
50. Basically the single right handed person is 1/100. For it to become 2/100 = 1/50, the number of left handed must decrease to 50-1=49. So from 99 to 49 is 50 left handed people must leave.
04:47 It would be easier to calculate this, if we would firstly multiply both sides by 100 (to get 100=2*x), and secondly divide both sides by 2 (to get 100/2 = x and x=50).
Better method to solve that algebra -
(99-x) / (100-x) = 98/100
Add and subtract 1 from 99 - x
(100-x-1) / (100-x) = 98/100
[(100-x) / (100-x)] - [1/(100-x)] = 98/100
1 - 1/(100-x) = 98/100
1 - 98/100 = 1/(100-x)
(100-98)/100 = 1/(100-x)
2/100 = 1/(100-x)
1/50 = 1/(100-x)
50 = 100-x
x = 100-50 = 50 Ans.
I read the thumbnail and immediately started guessing n/(n+1) values until I found the answer, then I started the video. The algebraic method and logic makes a lot of sense!
I'm 43 years old and this is the first time i've seen a useful implementation of something that i forgot in the last millenium. But the fact, that one person equals 2% in 50 people was just an intuitive thought at start of the video 😅
You just keep one right handed in the room, but he should represent 2% of the room instead of 1%, it means that you divided the room by 2.
Was afraid this could become a bloody affair, but al well ends well 😄! The explanation is a bit beyond the obvious, love it
While you were explaining the problem I thought intuitively, 50 sounds about right.
My first thought was to cut off one of one left-handed dudes left hand so they have no choice but to be right handed and now its 98%
If you did that then many of the other people would leave and mess up your percentages for good.
Another intuitive way to think of this is to change the side you're looking at. If only 1% are right handed, we need to get that to 2% in order to reduce the left handed side to 98%.
We can't double the number of right handed people to reach that target since we're only allowed to remove people, so we have to reduce the number of left handed people by 50%
I am sorry..I zoned out halfway through the proces and thought about if I could get the football court in recess before the other classes... just like 27 years ago when I was in math class....
i just watched 10 times how you switched your pens 1:03 ... awesome! and great content!
I find that it's simpler to see what the answer is if you look at it from the one right-handed persons perspective.
Originally heard this question with very watery potatoes.
(If a potato is 99% water by weight, what percentage of the weight would you need to dehydrate in order to make it 98% water)
I am more impressed on how he switches his markers.
This is a case where reality is not what is obvious.
What’s crazier is in order to get down to 97%, you’d have to remove sixteen and two thirds more left-handers from the room. To get down to 96%, you’d then have to remove eight and a third more left-handers. To decrease by 1% each time, the total people who STAY in the room must go from 100 to 50 to 33.33 to 25 to 20 to 16.66 to 14.285714 etc. Notice this follows the pattern of denominators 1/1, 1/2, 1/3, 1/4, 1/5, 1/6, 1/7 etc.
The number of people who need to LEAVE the room goes from 50 to 16.66 to 8.33 to 5 to 3.33 to 2.380952 to 1.7857142 etc. which follows a different pattern of denominators 1/(1x2), 1/(2x3), 1/(3x4), 1/(4x5), 1/(5x6), 1/(6x7) etc.
This math problem and solution actually makes you think about whether statistics actually reflect on social issues when a 1% drop in any social measurements may result in no actions whatsoever...i havent been able to rationalise the rest yet somebody help
Last time I saw that question, it was about a watermelon weighing 100 pounds that was 99% water and the question was how much water would have to evaporate from it for it to be 98% water.
In order for ONE right handed person to represent 2% of the total they have to be the only one out of 50 1/50 = 0.02 = 2%. One for every 50 equals two for every hundred in percentgage terms that means the room has to lose a total of 50 left-handed people.
My way of solution was, in the first case for 1 right-handed there are 99 left-handed. How many of left-handed has to leave so the ratio change to 1 right-handed to 49 left-handed (2-98). And you see the answer immediately. Interesting question though.
I thought about like this. Basically, if you remove one person, that's -1 for both the total and the number of left handed, which isn't exactly 98% in any case instead of 49 people out of 50 total people. And 99 - 49 is 50 people
You just need to figure out at what point the value of an individual doubles.
Nice seeing it all done out thoroughly.
My thought process just went "if we only have 1 righty, what number is one 2% of? Yep, 50, get rid of 50 lefties".
A simpler way to do this is to think of it from the right hand persons perspective, since the people we remove are only left handed, the 1 right handed person is constant, and therefore the percentage value they hold can help in calculating the rest, 1 is currently 1% of the total number of people, and since we need left handed people to become 98%, the remaining 2 % is the 1 Right handed person. So 1 went from being 1% of 100 to 2% of x. From there, it's straight forward. x*2/100=1. x=100/2=50. so the total number of people remaining in the room is 50, subtract that from the original number and you have the number of people that needs to be removed in order to match the required percentages.
I would think that to go from 1% Right handed to 2% right handed, you would need to half the total number of people, so 50 would need to leave the room so that 1 person equates to 2% of people.
I actually managed to do this as well after thinking about it for about 5 minutes and here’s my formula for this:
x/x+1 * 100 = 98%
Where x is the number of people left when there are 98% of people are left handed
and the x+1 ensures that there is still one person who isn’t left handed
With a bit of algebra you’ll get x = 49
Subtract this from 99 and your answer is 50 👏
I brute forced it with a calculator, but it's only 34 left-handed people that have to leave if you're ok with rounding down
The way I thought about this was simply what is the number of people at which 1 person represents 2% of the total number of people. 50 people total, 49 of whom are left-handed. Remove 50 from the original room to get there.
also you can think of it as 1 person being equal to 1% in the beginning and at the end each person is worth 2% of the total. so you can put it in an equation where the left handed have to equal 98% and the right handed being 2% meaning that there can only be a difference of 1 person between the two groups and the only way to get to 100 this way is with 49 and 50
I thought of it backwards. 1 right handed person can only be 2% of 50, so 50 sinister people have to leave.
without knowing the answer, by intuition it seems something similar like the old joke "A bat and a ball cost $1.10 in total... "
it depends on how it is formulated and that's why most of people fall into the trap
I guessed 50%. No math. Saw the problem with removing one immediately, and guessed that the next whole number must be with half the people gone.
I managed to figure this on TV as I was playing along after about 25 seconds and I was really proud of myself.
I just converted it to a ratio in my head and recognise the 49:1 was the only way to get to 98% with one left hander.
The one percent club is a great show, it really tests your problem solving and honestly I have more fun playing along than any other quiz show.
Easier to calculate just looking at the right handed people which stay the same. 1% before, 2% after, so the total number has to be half.
a simpler way of thinking about this is if I have 1 right handed person in a room, how many left handed people need to be in the room for right handed person to make up 2 percent of it
only 1 lefthanded person has to leave the room...
the catch is that a righthanded person has to enter, but the question never stated you cant add righthanded individuals to the room
Yes, or even simply add 48 left-handed people and 2 right-handed. That way you don't need to remove any left-handers and the answer to the question is 0.
You need to state the problem more precisely. As "exactly 98%", because a normal understanding is to make the fraction less than 0.985, because percentages without a decimal point are all rounded.
98% is precise. It is precisely equal to "exactly" 98%.
This is like saying that he needs to state that there are "exactly 100" people in the room or that "exactly 99%" of them are left-handed. The problem never stated nor implied that any of the values were rounded or approximations, nor does it ask for a rounded or approximated answer. It asks specifically for 98%
@@phiefer3 That is not how language works.
@@TrueThanny That's exactly how language works. If you accept that "100 people" is "exactly 100 people" then you have to also accept that "99%" is "exactly 99%" and that "98%" is "exactly 98%".
You cannot say that one requires "exactly" to be specified but another does not. Either they're all precise or none of them are.
@@phiefer3 Man, you are terrible at analogies.
It is beyond the comprehension of any sane, rational being how you think using _people_ as an example serves your argument.
People cannot be fractional.
Percentages are _always_ fractional.
I'd suggest trying again, but it's really better that you don't. Your hole is only growing, and it would be irresponsible to give you any advice beyond dropping that shovel.
@@TrueThannyIt is how language works. It is how math works. It is not how physics works, but this is not physics.
Plot twist: the right-handed person leaves-
Even bigger twist their is an ambidextrous person in the room .... figure that out
None have to leave if more can enter the room.
For instance 50 people of which exactly 48 are left-handed.
If no one may enter it's still none, but you might have to amputate.
Hah, I absolutely love that second solution; thinking outside the box to a whole new level.
50 left-handed people need to leave the room so that the single right-handed person represents 2% of the people instead of 1%
The first thing to do is just go the brute force route and see what % will be at some nice number that you can easily multiply into 100. Like 50, which just turns out to be the answer. Or you can understand that you have 1% and need 2%, thus you need twice more, which means that you need to divide the total by two without decreasing your 1%, thus you need 50 left-handed people to leave.
My first knee jerk reaction was 1, then I thought and realized that the ratio wouldn't change hardly at all if you did that, so I thought you needed to reduce the number by a substantial amount to increase it to 2%. The next obvious choice for that is to think about what number would keep the ratio closest to 100% and let 1 be a small percentage of the number. Obviously 50, being a round half of 100 makes sense to go to, so you divide 50 by 1 and you get 2%. Using logic to worm your way out of having to do complex equations is fun lol.
For me, the best mental method would be to think of the right handed (1) and put it as a constante, so to have 98% of left handed it means that 2% = 1, 100% = 2*50% => 2*x=98 => x=49
Then u know the total ammount of left handed guy and the original ammount so its easy
Much simpler: If x is the number that (approximates or) gives a 98% ratio: x/x+1 =98/100 reduces to x=49 ie 99-50