Oh that's so much smarter than me! I did it a long way. First I simplified by dividing by five. So four miles in three minutes. So I figured each minute you go one-and-one-third miles. And 60mph is a mile a minute. So one third of sixty is twenty. So 60 plus 20 is 80 mph. Your way is CRAZY smarter than mine! LOL! Just goes to show there's more than one way to get there, sometimes.
15 minutes is 1/4 hour so in 1 hour it will go 4 times as far, or 80 miles in an hour. Thus, it is going 80 Miles per hour. At least this time you didn't try to trick us with a poorly expressed equation that was specifically designed to confuse the intent of the problem. Much better.
Try this one. A race car must average 60 mph over two laps of a one mile race track. It averages 30 mph over the first lap. What average speed must it average over the second lap to enable it to average 60 mph over the two laps?
@@kevinreist7718 OK, now consider this. To average 60 mph over 2 laps of a 1 mile track will take 2 minutes, OK? Well, the race car just took 2 minutes to cover the first lap. Problem?
60 mph is a mile a minute, but in this instance the car went 20 miles in 1/4 of an hour. So it went 4 times that in an hour which is 80 miles in one hour
@@JohnBowl14690 the speed limit in my state is 70 and with the +10 miles per hour equals 80 and I would have to be going over 85mph to get pulled over in ohio.......
I drive through South Dakota and Wyoming where the freeway speed limit is 80 mph. I looked at the question and knew without doing the math. I lived it.
How hard can it be? Algebra?? Calculus? A child can see that 15 minutes is a quarter hour, so multiplying the 20 by 4 gives the obvious answer. Why look for problems where none exist?
The speed limit here is 20, 30, 40, 50 - 70mph at the most. How does an academic question ever amount to a problem if 99% of people can live a lifetime without needing the answer?
@johnnichol. I don’t understand - you were doing other peoples trigonometry for necessity or pleasure - or both? Are you saying that you count change better than me because of this or are you saying, presumably as an older person, that you have skills that others, broadly speaking, don’t need, except where you were able to fill the gap with your traditional skills?
@johnnichol. I do attempt to apply critical thought in the avoidance of inane and oriole tasks rather than in the performance of them if that’s what you mean. If you enjoy them that’s fine. Two of the great questions of our age are (1) to what extent should we be placing implicit faith in technology, and (2) why are we wasting our time on useless diversions in social media.
I used to be really good at solving word problems but when I saw this I was completely in at a loss thanks for bringing me back up to speed on this problem. As the old saying goes use it or lose it and it was long gone. Thanks again teach!
You have a computer. Can you simply follow a "harmless" formula? Go back to your computer and find the speed formula. We don't care about you "solving word problems." Also, check your comprehension reading level. Good day
This was the math problem i used to help prove the cops were lying when having to defend myself against 'false charges'. From the police reports that had the time of arrest and time of booking in cells...i asked the cops if they were slamming their handcuffed passenger that wasn't wearing a seatbelt back and forth by speeding around those sharp corners and when they said; 'No'. i then asked how they made a 35 min journey in 20 minutes without speeding and referenced and reminded the Judge of this very math problem...I won my case.
I have never done a problem like this,.. But I did it in my head in about 20 seconds with the correct answer. Since I already knew in 15 min you will go 15 miles at 60 mph so all i had to do was how long it will take to go another 5 miles in the same time frame and that is 4 times 5 which is 20 so 20 mph added to the 60 makes 80 mph.
60mph is a mile per minute. If it was travelling at 60 then it would do 15 miles in 15 mins. It does 20 miles which is a third more so the speed is a third more also than 60 so 80mph.
I have college student who could not work this one out. "You use a truck to take trash to a dump. The distance from your company to the dump sit is 25 miles. The speed limit is 60mph, allowing ten minutes for the actual dumping and completion of paperwordk, how long will it take the truck for a round trip from your compnay to the dump and back again? Ons student in the class of 20 got the right answer!
The simplest method is 15x4 as mentioned by some people here however the formula is valuable for numbers that are not perfectly divisible into 60. Like 16min or 23 min for example.
the cars speed is 20miles in 15 minutes!!! you asked an ambiguous question. the car is traveling ~0.02222 miles per second or did you assume an answer in miles per hour? i presume you want MPH. So 1 hour or 60 minutes divided by 15 minutes = 4. 4 * 20 miles = 80 80 miles in 60 minutes or 80 miles per 1 hour Your videos are very helpful especially on exponents and log. i now understand how to solve problems with exponents. thank you
60 / 15 = 4...4 x 20 =80...Always divide 60 by the minutes it took to go a certain distance then multiply that number by the miles you've driven. 20 miles in 18 minutes = 60 /18 = 3.3333....3.3333 x 20 miles = 66.6666 miles per hours.
when I first read the thumbnail… my quick answer was.. about $120 fine and 3 pts on your licenses (state may vary)… but I use that kind of math daily.. 80 MPH.. I know the math, hell I’m only a few credit hours short of being a math teacher.. it’s just I went to the ticket first before the actual number..
Lol. That's what I was thinking. I said, Well over 100 mph. 80 is speeding and it would take 15 to 20 minutes to run your license and receive your ticket. So you'd have to floor it in order to make up for lost time.
You don't have to take the 15 minutes on the side, convert it to hours and add that back into the equation. It can be done directly (in which case you do use 60 miles/1 hour): R T Conversion Factor Cancel Minutes Multiply Divide (20 miles/15 minutes) (60 minutes/1 hour) = (20 miles/15)(60/1 hour) = 1200 miles/15 hours = 80 mph ----> Average speed is 80 mph.
I'm looking at so many over-complicated replies with impressive looking but unnecessary equations when 15*4=60 so 20*4=80. It took me longer to type that than to calculate it in my head.
For me, it's easier just to set it up as a ratio or proportion. 15 over 20 = 60 over x .... and then multiply the left side by 4 over 4. Voila, 20 becomes 80.
to many ways to get 80 MPH. But like you i did it slightly different 20miles over 15minutes = 1.3333 miles per minute then multiplied by minutes in 1hour 1.3333330 * 60 = 80
@@dksaevs Interesting.... I like your scenario, and I have a slight variation on that one, too. I'd have left the fraction as imperfect, so 4/3. Four-thirds time 60 is 240/3, which is 80. Once in fractions, I really try to avoid going to decimal if at all possible--I guess that's how we were taught because of potential rounding errors. But your approach still stands on its own.
The SIMPLEST conversion is 15/60= 0.25, then apply the Speed formula D/T S=20/0.25= 80 MPH. Why do ALL these geniuses over here overthink a simple calculation, SHEESH?
In about 7 seconds I figured it out. I realized that since speed is usually measured in miles per hour, and that 15 minutes was a fourth of an hour, I just multiplied the 20 miles by four and figured the car would have to go 80 mph to go 20 miles. After I figured it out, I was glad to hear you state that common sense should give you the answer, but that if you changed the numbers, we would need a formula. So I will now watch the rest of the video because I want to know the formula for more difficult examples of this problem. You are a great teacher, btw.
I got the answer to the original question in seconds, knowing that there were 4/15 mins in an hour, etc. I then continued watching the video which completely messed with my brain. I read quite a lot of the suggestions posted looking for simpler methods, but again they were too convoluted. I am giving up at this point because the explanation is far too long.
@@pegasus8718 I understand. But it's good to learn different ways to solve problems. It's good exercise for the mind. Complex is more like it, not convoluted. 🙂
@@libertypastor1307 I fully agree that it’s good to learn new things, which is why I picked up on this video. Maths has always been a difficult subject for me and I have learnt more since leaving school than I did whilst there. I will return when I have more time to spare.
Greetings. The car's speed, velocity in MPH is 80. Using Distance, D = Time, T times Velocity, V we D = VT. First, we will convert minutes to hours by dividing 15 by 60 to get 1/4 hour. Now to find the Velocity, V we will use D = VT to get 20=1/4V MPH. That is V = 20×4 MPH = 80 MPH.
It's a trick question for the math overthinkers who want to apply complex formulae to problems not requiring one. For instance, the old chestnut of the bird on the front of a locomotive on a track doing 20 mph, flying at 40 mph to another loco closing in on the same track at 5 miles distance also doing 20 mph, touching it and instantly returning to the first loco at the same speed, and repeating this behavior until the locos crash. Problem: calculate the distance traveled by the bird. The math experts immediately recognize the problem as one requiring calculus, and proceed to calculate the distance in that way. However, all that is required is to calculate the time taken by the trains to meet and at 40 mph the bird's distance traveled is easily found, no calculus required. Sometimes it helps to be intelligent but not overly educated in math.
Just to make this more interesting, there would be no difference using the metric replacing the empirical measure but what would it be to explain the difference in comparing speed and distance between these two measures?
I don’t know because I don’t know where this takes place and the mode(s) used (4-wheeling off road shortcuts?), or a straight shot like you might find easily transversable through the Nevada desert.
I find the solution in about 10 seconds. How fast my mind was processing? ;) Seriously, I get that it was an easy problem and that I need to learn more about the method. So, I'll watch your video now.
Since 15 minutes is a quarter-hour and the desired rate is per-hour you simply multiply by 4 so that it's 80 miles per hour, and you're already done. I would barely even consider that math it's more like spatial reckoning or visualization. I used to get in trouble for not showing my work but how can I show work when there was none because I physically visualized it? Then I had to go back and backfill the "work" even though that wasn't how I got there.
It took me about me about EIGHTEEN SECONDS to get Eighty Miles Per Hour. NO, I am NOT a genius, WHY? Because my Math brain limit is Calculus One. The professor's teaching method/explanation grossly busted my super short fuse. The problem asked for Speed or Velocity in MPH. After reading the question, I quickly converted 15 Mins to 0.25(15/60) = Hour. Next, Velocity is defined as the Distance divided by Time or V=D/T. 20/0.25= 2000/25 =80. Both 0.25 and 20, obviously were multiplied by 100 to simplify the calculation. The Velocity is 80 MPH. BTW, Arithmetic, got it ARITHMETIC. MATH is for the geniuses. Arithmetic is for US not so brain-powered. Thank you
Yes, but what about the speed limit where you are driving!? The formula I used for that was E=mc2. But I ended up in some alternative solar system and I have no clue where I am. And I need to get home for dinner!
imo, the following equation is easier to use: we know we have 15 minutes.. and there are 60 minutes to an hour, so in the case of 15 minutes, we can multiply both parts of the equation by 4 in order to reach our answer, ez.. but let's say we have another car that goes 20 miles in 13 minutes. we can simply do the following: the units of time we are given is minutes, the units we want is hours, so in order to convert the speed of the vehicle from miles per minute to miles per hour. we know there's 60 minutes (units) in 1 hour, so therefor, we can divide the speed of the vehicle 20 hours per minute by the number of minutes that the car was traveling, 13 minutes, and then multiply it by 60 as there are 60 units in 1 hour. that looks as followed 20 / 13 * 60 = 92.3 mph this is the same method you can use if you are given a number is is not 100%.. ie.. 37% of the whole is 533. to find out what 100% is you would simply do. 533 / 37 * 100 = 1,440.54 you first find out what 1% is by dividing the amount by the percent that you know that it is.. and then you multiply by 100 in order to find out what 100% is. then finally.. if you are dealing with a speed given in mph but you want kph (for example).. then you simply first figure out the speed in the given measurement type.. and then you convert your answer to the type that is being asked for.
There is an easy quick way to determine either Time, Distance, or Speed if 2 parts are known by remembering the formula / 60 D Street. Draw a circle and draw a horizontal line though it. Next, draw a vertical line from the middle of the Horizontal line down to the bottom of the circle. Now put 60xD (Distance) in the Top half of the circle - then put the abbreviation for street (ST) in the Bottom half with "S" (Speed) on one side of the vertical line and "T" (Time) on the other. We want to know the Speed in this Problem so we are going to multiply 60 X Distance (20)= 1200. If we are after speed then we divide the 1200 by the Time (15) = 80 mph // If we know the speed (80) and time (15 minutes) we multiply the speed and the time (1200) and divide by 60 will give us the distance (20). If we know the distance (20) and speed (80), we multiply the distance (20) by 60 (1200) and divide by the Speed (80) will will get the time (15). All this just by remembering 60D Street in a circle. We are basically multiplying the bottom half of the circle and dividing by the top. It's a handy formula remember to have when navigating on the water. Of course, in this problem 20 x 4 does the same thing.🙂
80 MPH 15 minutes is 1/4 of an hour, so 4 sets of 15 minutes per hour, and 4 sets of 20 miles traveled, per hour. 4 sets of 20 miles traveled in 1 hour, is 80 miles traveled in that hour, so 80 MPH.
In my opinion, and that's what it is, an opinion, it is because younger people believe math is something done on a phone or computer, not in their head. They live and totally depend on their phone for most things, and thus lack many skills and basic knowledge and instead depend on the phone to do it for them. What they need to be taught is that they are taught these things because they NEED TO KNOW THEM. They are not drones, they are humans at the top of the intellect scale. Or....maybe they are not?
Nice explanation but.....This could have been easily explained in 5 to 7 min max. Sometimes the explanation can be so long and detailed, the essence of learning the concept is completely lost. Thanks for sharing with us though.
It would be well over 100 mph. 80 is speeding in most areas so they'd get pulled over and ticketed. That would take around 15 to 20 minutes. So in order to make up for lost time you'd have to floor it.
15 minutes is one quarter (1/4) of one hour (60 minutes) so we multiply 20 x 4 to get the answer, simple as that. It doesn't need a 15 minute video to explain this !
Alternatively, you could do a formula that also works for any distance & any time interval. Distance Divide Minutes Times 60 20 Divide 15 = 1.333’ Times 60 = 80(mph) Second Example 14 Miles in 2 Minutes 14 / 2 = 7 7 X 60 = 420(mph)
Or you could just Divide the 20/15 and say the car was going 1and 1/3 mile per minute. I always likes the expresion he was going down the road at a mile per minute instead of saying 60 miles per hour!!! Math is fun.. any corrections appreciated...I do now realize you said MPH>>>
Did you forget or bother to convert 15 mins to an hour or 15/60- 0.25 Hours? What "Math?" Try simple Arithmetic. Conclusion you are lost not to mention ridiculously WRONG.
The question is ambiguous though. It would be fine if it said “a car travelling at a constant speed…” or asked “what is its average speed”. But current wording it could have stopped for a few minutes then done the rest at 120mph!
Wrong approach Mr. GED/JoeBlow: IF you know how to use the computer, you should have looked for the Speed formula Speed= D/T. Plug in the values>>80MPH. Just because you guessed it right does not mean your calculation was right; it was NOT, GOT IT? Right is Right, Wrong is Wrong, Sir, Move on...
That took me about 10 seconds to read and then formulate the answer. 80 mph. About as hard as traveling at 60mph how many miles do you travel in one hour.
60 (minutes in an hour) divided by 15 = 4. Now times the 20 miles by 4 = 80mph. Now, what if you went the same distance but did it in 10 minutes? Same equation: 60 divided by 10 = 6. Six times 20 = 120 mph. Yes, I know, that's an insane speed to be driving in the US. 😨😱
I made a quick guestimate of 45 mph and divided 45 by 60 giving me 0.75 miles per minute. I then multiplied .75 * 20 and had my answer. It was a lucky quick first guess but would have gotten me in the ballpark if the distance had been plus or minus a few miles from the given problem.
I KNOW BASIC MATH, BUT I HATE MATH, PERIOD. I WAS PUNISHED FOR NOT GETTING IT AS A CHILD. TOOK ME FOREVER TO LEARN THE CLOCK LOL, NO ONE EVER EXPLAINED IT TO ME UNTIL MY GRANDMOTHER CAME FOR A VISIT. I NEVER HAD ALGEBRA, HATED FRACTIONS, ETC. SO I STILL FEEL INADEQUATE AND DENSE WHEN IT COMES TO MEASUREMENTS. BA HUMBUG, LOL
Is it ok if I did it in 5 seconds in my mind without even playing the video? Or should I watch these 15 minutes? I'm aksing cuz even if I got it correct I don't know if there's something new that this video could teach me, maybe a new way of calculating stuff, I wanna know but at the same time I don't wanna go through the whole thing, can anybody who's watched it tell me what was in it?
Common sense would be no exact answer as the speed can vary. You should have asked for an...average speed. I just outsmarted a math teacher in his own question.
I also used the fact that 15 minutes is a quarter hour, so the speed is 20 miles per quarter hour which simplifies to 80 mph.
Oh that's so much smarter than me! I did it a long way.
First I simplified by dividing by five. So four miles in three minutes. So I figured each minute you go one-and-one-third miles. And 60mph is a mile a minute. So one third of sixty is twenty. So 60 plus 20 is 80 mph.
Your way is CRAZY smarter than mine! LOL!
Just goes to show there's more than one way to get there, sometimes.
Yep. Simple
It’s 160mp2h.
Exactly, so why the 15 minute video? 😂😂
Took me a minute and I don't like maths .
15 minutes is 1/4 hour so in 1 hour it will go 4 times as far, or 80 miles in an hour. Thus, it is going 80 Miles per hour. At least this time you didn't try to trick us with a poorly expressed equation that was specifically designed to confuse the intent of the problem. Much better.
That is exactly how I figured it out.!!! 👍🏽😂
Try this one. A race car must average 60 mph over two laps of a one mile race track. It averages 30 mph over the first lap. What average speed must it average over the second lap to enable it to average 60 mph over the two laps?
@@phildavenport4150 90 mph, because 30 mph+90 mph=120 mph/2=60 mph.
@@kevinreist7718 OK, now consider this. To average 60 mph over 2 laps of a 1 mile track will take 2 minutes, OK? Well, the race car just took 2 minutes to cover the first lap. Problem?
@@phildavenport4150 The only problem is that a time constraint was not part of the original story problem.
60 mph is a mile a minute, but in this instance the car went 20 miles in 1/4 of an hour. So it went 4 times that in an hour which is 80 miles in one hour
From basic physics: e = v x t, so v=e/t or v=20 miles/0.25 h or 80 miles/h.
Velocity is a Vector, try Speed.
Wow! This was sooooooo easy! 20 miles in 1/4 hour x4 = 80 miles! 10 seconds at most to solve!
Wrong answer. Cop pulled you over already at 70mph.
@@JohnBowl14690 the speed limit in my state is 70 and with the +10 miles per hour equals 80 and I would have to be going over 85mph to get pulled over in ohio.......
For some!
staged
Took me about 5 seconds
I drive through South Dakota and Wyoming where the freeway speed limit is 80 mph. I looked at the question and knew without doing the math. I lived it.
maths
So what? So much for Mr. Sarcastic, ahah?
@@marty8370 Try Arithmetic, DUH? Yes, that simple.
If people cannot solve this in 10 seconds in their head there is a much bigger problem
How hard can it be? Algebra?? Calculus? A child can see that 15 minutes is a quarter hour, so multiplying the 20 by 4 gives the obvious answer. Why look for problems where none exist?
The speed limit here is 20, 30, 40, 50 - 70mph at the most. How does an academic question ever amount to a problem if 99% of people can live a lifetime without needing the answer?
@johnnichol. I don’t understand - you were doing other peoples trigonometry for necessity or pleasure - or both? Are you saying that you count change better than me because of this or are you saying, presumably as an older person, that you have skills that others, broadly speaking, don’t need, except where you were able to fill the gap with your traditional skills?
@johnnichol. I do attempt to apply critical thought in the avoidance of inane and oriole tasks rather than in the performance of them if that’s what you mean. If you enjoy them that’s fine.
Two of the great questions of our age are (1) to what extent should we be placing implicit faith in technology, and (2) why are we wasting our time on useless diversions in social media.
I used to be really good at solving word problems but when I saw this I was completely in at a loss thanks for bringing me back up to speed on this problem. As the old saying goes use it or lose it and it was long gone. Thanks again teach!
You have a computer. Can you simply follow a "harmless" formula? Go back to your computer and find the speed formula. We don't care about you "solving word problems." Also, check your comprehension reading level. Good day
About 80 mph. Time for an attorney, DMV driver training, and hope my license isn't revoked!!!
LMAO, time to move, many places with 80 mph limit
@@RobS282👍 85mph in Texas
About time for you to audit at the Comedy Central station Ms. Annette, we got enough payasos as it is.
This needs to be condensed. Dragged out.
I really hope that everybody, older that Junior High can solve this in about 1.5 sec!!!!
It took me 1.5 seconds then another minute looking for the clue to what I assumed was a trick question.
I must have a suspicious mind.
This was the math problem i used to help prove the cops were lying when having to defend myself against 'false charges'.
From the police reports that had the time of arrest and time of booking in cells...i asked the cops if they were slamming their handcuffed passenger that wasn't wearing a seatbelt back and forth by speeding around those sharp corners and when they said; 'No'. i then asked how they made a 35 min journey in 20 minutes without speeding and referenced and reminded the Judge of this very math problem...I won my case.
I have never done a problem like this,.. But I did it in my head in about 20 seconds with the correct answer. Since I already knew in 15 min you will go 15 miles at 60 mph so all i had to do was how long it will take to go another 5 miles in the same time frame and that is 4 times 5 which is 20 so 20 mph added to the 60 makes 80 mph.
60mph is a mile per minute. If it was travelling at 60 then it would do 15 miles in 15 mins. It does 20 miles which is a third more so the speed is a third more also than 60 so 80mph.
I realized the answer was 80 mph, when I remembered that 15 minutes was a 1/4 of one hour.
(20 miles/min) x (60 min/1 hr) = 80 miles/hr
I have college student who could not work this one out. "You use a truck to take trash to a dump. The distance from your company to the dump sit is 25 miles. The speed limit is 60mph, allowing ten minutes for the actual dumping and completion of paperwordk, how long will it take the truck for a round trip from your compnay to the dump and back again? Ons student in the class of 20 got the right answer!
Other than the obvious 20x4 solution, you can also solve it as a ratio: 15 is to 20 as 60 is to x, which comes down to 3x = 240; x = 80
What about "Y"??? YOU LEFT OUT Y!
😂 gosh ... that just 🤯 my mind lolol.. I flet so dumb when you showed us how lol...
The simplest method is 15x4 as mentioned by some people here however the formula is valuable for numbers that are not perfectly divisible into 60. Like 16min or 23 min for example.
Multiplying 15 by 4 is the SIMPLEST method of getting the wrong answer. 😊
the cars speed is 20miles in 15 minutes!!! you asked an ambiguous question. the car is traveling ~0.02222 miles per second or did you assume an answer in miles per hour? i presume you want MPH. So 1 hour or 60 minutes divided by 15 minutes = 4. 4 * 20 miles = 80 80 miles in 60 minutes or 80 miles per 1 hour
Your videos are very helpful especially on exponents and log. i now understand how to solve problems with exponents. thank you
60 / 15 = 4...4 x 20 =80...Always divide 60 by the minutes it took to go a certain distance then multiply that number by the miles you've driven. 20 miles in 18 minutes = 60 /18 = 3.3333....3.3333 x 20 miles = 66.6666 miles per hours.
Simple mental arithmetic. 80mph. Took me about 1 second to figure out.
when I first read the thumbnail… my quick answer was.. about $120 fine and 3 pts on your licenses (state may vary)… but I use that kind of math daily.. 80 MPH.. I know the math, hell I’m only a few credit hours short of being a math teacher.. it’s just I went to the ticket first before the actual number..
Lol. That's what I was thinking. I said, Well over 100 mph. 80 is speeding and it would take 15 to 20 minutes to run your license and receive your ticket. So you'd have to floor it in order to make up for lost time.
You don't have to take the 15 minutes on the side, convert it to hours and add that back into the equation. It can be done directly (in which case you do use
60 miles/1 hour):
R T Conversion Factor Cancel Minutes Multiply Divide
(20 miles/15 minutes) (60 minutes/1 hour) = (20 miles/15)(60/1 hour) = 1200 miles/15 hours = 80 mph ----> Average speed is 80 mph.
Why not just multiply by 4.
That's much more complicated than it should be.
Speed when? Start, finish or average?
Were there any stop signs up ahead or being pulled over for speeding ?
I'm looking at so many over-complicated replies with impressive looking but unnecessary equations when 15*4=60 so 20*4=80.
It took me longer to type that than to calculate it in my head.
Public education. Where children learn their self image is wonderful but nothing much else.
For me, it's easier just to set it up as a ratio or proportion. 15 over 20 = 60 over x .... and then multiply the left side by 4 over 4. Voila, 20 becomes 80.
to many ways to get 80 MPH. But like you i did it slightly different 20miles over 15minutes = 1.3333 miles per minute then multiplied by minutes in 1hour 1.3333330 * 60 = 80
@@dksaevs Interesting.... I like your scenario, and I have a slight variation on that one, too. I'd have left the fraction as imperfect, so 4/3. Four-thirds time 60 is 240/3, which is 80. Once in fractions, I really try to avoid going to decimal if at all possible--I guess that's how we were taught because of potential rounding errors. But your approach still stands on its own.
Simple conversion problem. 20/15 = mpm convert to mph by multiplying by 60. Obviously because there is 60 minutes in an hour.
The SIMPLEST conversion is 15/60= 0.25, then apply the Speed formula D/T S=20/0.25= 80 MPH. Why do ALL these geniuses over here overthink a simple calculation, SHEESH?
Is the academy for 2nd year pupils?
In about 7 seconds I figured it out. I realized that since speed is usually measured in miles per hour, and that 15 minutes was a fourth of an hour, I just multiplied the 20 miles by four and figured the car would have to go 80 mph to go 20 miles.
After I figured it out, I was glad to hear you state that common sense should give you the answer, but that if you changed the numbers, we would need a formula. So I will now watch the rest of the video because I want to know the formula for more difficult examples of this problem.
You are a great teacher, btw.
I got the answer to the original question in seconds, knowing that there were 4/15 mins in an hour, etc. I then continued watching the video which completely messed with my brain. I read quite a lot of the suggestions posted looking for simpler methods, but again they were too convoluted. I am giving up at this point because the explanation is far too long.
@@pegasus8718 I understand. But it's good to learn different ways to solve problems. It's good exercise for the mind. Complex is more like it, not convoluted. 🙂
@@libertypastor1307 I fully agree that it’s good to learn new things, which is why I picked up on this video. Maths has always been a difficult subject for me and I have learnt more since leaving school than I did whilst there. I will return when I have more time to spare.
@@pegasus8718 👍
Blah, blah Mr. Seven Seconds or Einstein, Jr; WOW, your 200 IQ impresses a lot of people except MOI!!!!
Greetings. The car's speed, velocity in MPH is 80. Using Distance, D =
Time, T times Velocity, V we
D = VT. First, we will convert minutes to hours by dividing 15 by 60 to get 1/4 hour. Now to find the Velocity, V
we will use D = VT to get 20=1/4V MPH. That is V = 20×4 MPH = 80 MPH.
It's a trick question for the math overthinkers who want to apply complex formulae to problems not requiring one. For instance, the old chestnut of the bird on the front of a locomotive on a track doing 20 mph, flying at 40 mph to another loco closing in on the same track at 5 miles distance also doing 20 mph, touching it and instantly returning to the first loco at the same speed, and repeating this behavior until the locos crash. Problem: calculate the distance traveled by the bird. The math experts immediately recognize the problem as one requiring calculus, and proceed to calculate the distance in that way. However, all that is required is to calculate the time taken by the trains to meet and at 40 mph the bird's distance traveled is easily found, no calculus required. Sometimes it helps to be intelligent but not overly educated in math.
Speed, not velocity. Velocity is a vector ( has a direction and speed).
@@phildavenport4150 Go play with your "blank" bird.
Just to make this more interesting, there would be no difference using the metric replacing the empirical measure but what would it be to explain the difference in comparing speed and distance between these two measures?
@@johnnichol9412 Thank you
thanks for making something thats easy become difficult
60 miles per hour
80 mph. Did it in my head. 20 miles in 15 minutes = 40 miles in 30 minutes. 30 minutes x 2 = 1 hour = 40 miles x 2 = 80 mph.
I don’t know because I don’t know where this takes place and the mode(s) used (4-wheeling off road shortcuts?), or a straight shot like you might find easily transversable through the Nevada desert.
The car only went 20 miles. It's speed is now zero. 😂
I like the way you think. I fell for the 80 MPH trick, but you are 100% correct based on the info provided.
He prolly mint wat wuz the car's speed in this prom ! or is it prolum ?
I find the solution in about 10 seconds. How fast my mind was processing? ;)
Seriously, I get that it was an easy problem and that I need to learn more about the method. So, I'll watch your video now.
I had a problem with these sort of math problems.....still do!😂Never got math, still don't!
I'm betting that they weren't driving a Yugo !! 🤣👍🏻
Since 15 minutes is a quarter-hour and the desired rate is per-hour you simply multiply by 4 so that it's 80 miles per hour, and you're already done. I would barely even consider that math it's more like spatial reckoning or visualization. I used to get in trouble for not showing my work but how can I show work when there was none because I physically visualized it? Then I had to go back and backfill the "work" even though that wasn't how I got there.
How many stop lights?
I suck at math, did this in my head in 4 seconds
Very good channel,but, boy it beats around the bush!
80 miles an hour
Does over the speed limit count as an answer?
That was simple!
It took me about me about EIGHTEEN SECONDS to get Eighty Miles Per Hour. NO, I am NOT a genius, WHY? Because my Math brain limit is Calculus One. The professor's teaching method/explanation grossly busted my super short fuse. The problem asked for Speed or Velocity in MPH. After reading the question, I quickly converted 15 Mins to 0.25(15/60) = Hour. Next, Velocity is defined as the Distance divided by Time or V=D/T. 20/0.25= 2000/25 =80. Both 0.25 and 20, obviously were multiplied by 100 to simplify the calculation. The Velocity is 80 MPH.
BTW, Arithmetic, got it ARITHMETIC. MATH is for the geniuses. Arithmetic is for US not so brain-powered. Thank you
I was reminded that velocity is a vector. Please change the V to an S(Speed), again thanks.
I did it in my head and was thinking it was 80 MPH, but since the video was 15:38 long, I thought I must have missed something. Nope.
I use the ‘ratio’ formula.
Simple unit conversation:
20 miles/15 minutes x 60 minutes/hour
20 x 60 / 15 = 80
Minutes cancel out to give miles/hour
Yes, but what about the speed limit where you are driving!? The formula I used for that was E=mc2. But I ended up in some alternative solar system and I have no clue where I am. And I need to get home for dinner!
imo, the following equation is easier to use:
we know we have 15 minutes.. and there are 60 minutes to an hour, so in the case of 15 minutes, we can multiply both parts of the equation by 4 in order to reach our answer, ez.. but let's say we have another car that goes 20 miles in 13 minutes. we can simply do the following:
the units of time we are given is minutes, the units we want is hours, so in order to convert the speed of the vehicle from miles per minute to miles per hour.
we know there's 60 minutes (units) in 1 hour, so therefor, we can divide the speed of the vehicle 20 hours per minute by the number of minutes that the car was traveling, 13 minutes, and then multiply it by 60 as there are 60 units in 1 hour. that looks as followed
20 / 13 * 60 = 92.3 mph
this is the same method you can use if you are given a number is is not 100%.. ie.. 37% of the whole is 533. to find out what 100% is you would simply do.
533 / 37 * 100 = 1,440.54
you first find out what 1% is by dividing the amount by the percent that you know that it is.. and then you multiply by 100 in order to find out what 100% is.
then finally.. if you are dealing with a speed given in mph but you want kph (for example).. then you simply first figure out the speed in the given measurement type.. and then you convert your answer to the type that is being asked for.
There is an easy quick way to determine either Time, Distance, or Speed if 2 parts are known by remembering the formula / 60 D Street. Draw a circle and draw a horizontal line though it. Next, draw a vertical line from the middle of the Horizontal line down to the bottom of the circle. Now put 60xD (Distance) in the Top half of the circle - then put the abbreviation for street (ST) in the Bottom half with "S" (Speed) on one side of the vertical line and "T" (Time) on the other. We want to know the Speed in this Problem so we are going to multiply 60 X Distance (20)= 1200. If we are after speed then we divide the 1200 by the Time (15) = 80 mph // If we know the speed (80) and time (15 minutes) we multiply the speed and the time (1200) and divide by 60 will give us the distance (20). If we know the distance (20) and speed (80), we multiply the distance (20) by 60 (1200) and divide by the Speed (80) will will get the time (15). All this just by remembering 60D Street in a circle. We are basically multiplying the bottom half of the circle and dividing by the top. It's a handy formula remember to have when navigating on the water. Of course, in this problem 20 x 4 does the same thing.🙂
You’re right, that seems both quick and easy!
@@tonym2513 Applying the Speed formula is simpler than that circle fecal garbage stuff...
@@luisaalemanjr9037 r/whoosh
80 MPH
15 minutes is 1/4 of an hour, so 4 sets of 15 minutes per hour, and 4 sets of 20 miles traveled, per hour.
4 sets of 20 miles traveled in 1 hour, is 80 miles traveled in that hour, so 80 MPH.
an Hour is 60 min there is 4x15=60 so to figure the rate you have to multiply 20 times 4 =80mph.
In my opinion, and that's what it is, an opinion, it is because younger people believe math is something done on a phone or computer, not in their head. They live and totally depend on their phone for most things, and thus lack many skills and basic knowledge and instead depend on the phone to do it for them. What they need to be taught is that they are taught these things because they NEED TO KNOW THEM. They are not drones, they are humans at the top of the intellect scale. Or....maybe they are not?
It is NOT "math." Try simple Arithmetic. Thank you
Nice explanation but.....This could have been easily explained in 5 to 7 min max. Sometimes the explanation can be so long and detailed, the essence of learning the concept is completely lost. Thanks for sharing with us though.
Goodness...did this in 10sec in my head. The method looks very complicated..
My process
15mins = quarter of an hour
4 quarters (1hr) x 20mph = 80mph
When you need 15 minutes to explain this; you're explaining 1,3333 per mile.
It would be well over 100 mph. 80 is speeding in most areas so they'd get pulled over and ticketed. That would take around 15 to 20 minutes. So in order to make up for lost time you'd have to floor it.
15 minutes is one quarter (1/4) of one hour (60 minutes) so we multiply 20 x 4 to get the answer, simple as that. It doesn't need a 15 minute video to explain this !
Alternatively, you could do a formula that also works for any distance & any time interval.
Distance Divide Minutes
Times 60
20 Divide 15 = 1.333’
Times 60 = 80(mph)
Second Example
14 Miles in 2 Minutes
14 / 2 = 7 7 X 60 = 420(mph)
There is a formula set/developed before you were born by smarter people than you, move on. Good Day
80 figured it right off.
Or you could just Divide the 20/15 and say the car was going 1and 1/3 mile per minute. I always likes the expresion he was going down the road at a mile per minute instead of saying 60 miles per hour!!! Math is fun.. any corrections appreciated...I do now realize you said MPH>>>
Did you forget or bother to convert 15 mins to an hour or 15/60- 0.25 Hours? What "Math?" Try simple Arithmetic. Conclusion you are lost not to mention ridiculously WRONG.
The question is ambiguous though. It would be fine if it said “a car travelling at a constant speed…” or asked “what is its average speed”. But current wording it could have stopped for a few minutes then done the rest at 120mph!
Dangerously fast. Most people would call it reckless.
It all depends on the road and the car.
My car is just starting to run right at 80.......
I only have a GED. But I thought, there's 4 - 15 minute quarters in an hour. Multiply 20 x 4 = 80.
Wrong approach Mr. GED/JoeBlow: IF you know how to use the computer, you should have looked for the Speed formula Speed= D/T. Plug in the values>>80MPH. Just because you guessed it right does not mean your calculation was right; it was NOT, GOT IT? Right is Right, Wrong is Wrong, Sir, Move on...
That took me about 10 seconds to read and then formulate the answer. 80 mph. About as hard as traveling at 60mph how many miles do you travel in one hour.
They were not driving in Wales where the speed limit is 20 mph.
Is this a junior school question
Using simple arithmetic to come up with an answer of 80 mph i,e, 4 sets of 20 miles for the 4 sets of 15 minutes.
Depends on traffic.
I think he just made it more complicated and what it needed to be😂
He is just trying to justify his existance
ask him what time is it, he'll tell you how to build a watch
@@haj811ha ha you are so right. Professors/teachers talk endlessly. Actually his talk time should have been 2 minutes while solving the problem. Max.
¡I bet you failed Algebra 1 in HS!
exactly, you can do it in your head in a under a minute.
Depends on how big the wheels are ....
Is the car powered by gas or electric? In common core math that would matter.
60 (minutes in an hour) divided by 15 = 4. Now times the 20 miles by 4 = 80mph. Now, what if you went the same distance but did it in 10 minutes? Same equation: 60 divided by 10 = 6. Six times 20 = 120 mph. Yes, I know, that's an insane speed to be driving in the US. 😨😱
Wrong formula Eistein. Try S=D/T= D 20 miles/T (15/60) or 0.25 = 80 MPH. Very simple instead of your fecal garbage approach...
I made a quick guestimate of 45 mph and divided 45 by 60 giving me 0.75 miles per minute. I then multiplied .75 * 20 and had my answer. It was a lucky quick first guess but would have gotten me in the ballpark if the distance had been plus or minus a few miles from the given problem.
You weren’t close. The answer is 80mph.
@@tonym2513 Yep. I was solving for 15 miles being traveled in 20 minutes, not 20 miles in 15! Oops.
@@dr.emilschaffhausen4683 I concur, doctor.
I did the numbers in my head and guessed 80 mph.
Now you just need to work out how much your speeding fine is going to cost you for every MPH you've driven over the speed limit! lol
A question for a normal pupil of std. 4 of the primary schooĺ in Mauritius......
I KNOW BASIC MATH, BUT I HATE MATH, PERIOD. I WAS PUNISHED FOR NOT GETTING IT AS A CHILD. TOOK ME FOREVER TO LEARN THE CLOCK LOL, NO ONE EVER EXPLAINED IT TO ME UNTIL MY GRANDMOTHER CAME FOR A VISIT. I NEVER HAD ALGEBRA, HATED FRACTIONS, ETC. SO I STILL FEEL INADEQUATE AND DENSE WHEN IT COMES TO MEASUREMENTS. BA HUMBUG, LOL
Is it ok if I did it in 5 seconds in my mind without even playing the video? Or should I watch these 15 minutes? I'm aksing cuz even if I got it correct I don't know if there's something new that this video could teach me, maybe a new way of calculating stuff, I wanna know but at the same time I don't wanna go through the whole thing, can anybody who's watched it tell me what was in it?
Four times the speed limit means losing your licence.
This is not mathematics but simple arithmetic.
4 x 15 = 60 minutes. 4 x 20 = 80 miles, - 80 miles per 1 hour. ( common denominator = 4 )
The car immediately broke down at 20 miles so the answer is 20 mph
The way I do I ,is four fifteens are sixty ,so four twenties are eighty ,twenty for each quarter ,easy for me i do all mat in my head
Common sense would be no exact answer as the speed can vary. You should have asked for an...average speed. I just outsmarted a math teacher in his own question.
Illegal in all but Nevada and Montana.
I lost the will to live watching this video in fact I grew a beard waiting for the formula
So easy, very fast.
129 km\h
All you know is that at one point the car had to be traveling at 80 mph at one point. MVT?
Car traveled 20 miles in 15 min, so 20 /15 = 1.3333 miles per min, therefore per 1 hour (60 min), 1.3333 x 60 = 80 mph.
I was good in math but these stupid speed questions never helped me in life
Add another 39 minutes for his citation!