Kids maths home work

[fever28]

Hate to admit,I don't know how to do this.
For 10 year old
This type of question
Tom has a cd collection which he has sorted into three categories : classic, rock and pop. He has four times as many pop as classic, and three times as many rock as classical . Altogether Tom has 80 CDs
How many classical
How many rock
How many pop

[Quizmonkey]

Use algebra: give each category a letter (C, R and P) then construct the equations and work out together to get the values.

[hc4361]

40 pop
10 classic
30 rock

[caspersuzy]

40 pop,30 rock,10 classical

[redcrx]

probably the wrong way but:

classical is the one thats multiplied.
suggest classical is 1, then pop is 4x1 and rock is 3x1 (total 8)

80/8=10

so multiply up until you get total 80. classical 1x10 pop 4x10 rock 3x10.

total 80

[Captain2]

Let x = number of classics
so 4x = number of pop, and
so 3x = number of rock
then x + 4x + 3x = 80
so x = 80/8
x = 10 (Classics)
and pop = 40 and rock = 30
Hope that makes sense

[fever28]

Hi I was after method, I did get it right but as the other poster from an initial guess, thought there would be a straight forward method considering age. Thanks for quick responses

[fever28]

Thanks got it, sorry would have accepted both credit to redcrx sorry

[factor-fiction]

Yes, these answers are opf course correct.
One way to look at it is to imagine his CDs in equal size boxes and he has 4 boxes of pop, 3 boxes of rock and one box of classical. That's 8 boxes in total. He has 80 CDs in total so each of the boxes 10 CDs.
So that's 40, 30, 10. That's exactly what redcrx did and I'm sure the others did it pretty much the same way.

[redcrx]

i cant recall at 10 if the children do algebra in the way of x's etc. but my way was same, just a more basic way of doing exactly same thing, as children can often be put off by x,y sums.

[factor-fiction]

Children of 10 would not normally be expected to us algebra. This will have arisen as ratio problem.

One way for many pupils to work this out is to use a pile of 80 coins and sort them into piles: 4 for pop, 3 for rock, 1 for classical; again 4 for pop, 3 for rock, 1 for clasical... and so on until all the coins have gone.
Then when they have mastered that approach ask them to see if they can find a quicker way

[Old_Geezer]

C + P + R = 80
C + 4C + 3C = 80
8C = 80
C = 10

P = 4C = 40

R = 3C = 30