Q.16. At the end you stated, 'therefore c is an even number' when you meant to say the given formula is even. C can be either odd or even. Great video. Many thanks.
For Q20 cant you work it out by multiplying 5 by 3 and square it as it is stated that it's directly proportional so you just reverse what happened to 36 to get "a" when y = 5
for question 15, I found doing 9x10x10x2 a lot more simple. There are only 9 digits that aren't 0. There are 10 single digits for the hundreds and tens places in the four digit number. And only 2 single digit numbers (0 and 5) that'll work with the whole number being divisible by 5.
I got 1799 for the first one because 1000-9995 (last multiple of 5 with four digits) and obviously 8x200 equals 1600+199 (no multiple of 10000) equals 1799?
Q.20. 5=1/3SQRROOT(x): Squaring both sides is one way. The other way would be to multiply both sides by 3 first and then square both sides. It will give the same answer. I don't understand the need to square the 1/3.
Q.16. At the end you stated, 'therefore c is an even number' when you meant to say the given formula is even. C can be either odd or even. Great video. Many thanks.
You are amazing sir!
For Q20 cant you work it out by multiplying 5 by 3 and square it as it is stated that it's directly proportional so you just reverse what happened to 36 to get "a" when y = 5
I Ogi I Hi - yes, that would be no problem. You’d get 15 = roota ... if you then square you’ll get 225 = a. I think your way is much easier :-) Best S
When watching the video that's what I thought, I was going to comment it and then I saw your comment.
for question 15, I found doing 9x10x10x2 a lot more simple. There are only 9 digits that aren't 0. There are 10 single digits for the hundreds and tens places in the four digit number. And only 2 single digit numbers (0 and 5) that'll work with the whole number being divisible by 5.
Hi - yes, that’s a great way of working through this question and thank you for your comment. All very best S :-)
I got 1799 for the first one because 1000-9995 (last multiple of 5 with four digits) and obviously 8x200 equals 1600+199 (no multiple of 10000) equals 1799?
do you know where I can get exam questions like number 15? as I struggle a lot on these questions
Hannah Abdi Hi - try mathsgenie.co.uk/gcse.html, in ‘The product rule for counting’ on the grade 6 questions. Hope they help and all best S
Q.20. 5=1/3SQRROOT(x): Squaring both sides is one way. The other way would be to multiply both sides by 3 first and then square both sides. It will give the same answer. I don't understand the need to square the 1/3.