Stuck on maths question

(32 Posts)
hercules1 Tue 25-Feb-14 22:28:44

Okay, got a question from the rules of maths book that I can't work out.

In a survey conducted in a junior school it was found that on one evening four times as many children watched BBC one as watched BBC2, and that twice as many children watched ITV as watch BBC one. If there were 310 children in the school, how many children watched each channel?

Any help gratefully received.

lisad123everybodydancenow Tue 25-Feb-14 22:35:14

Message withdrawn at poster's request.

Skiingmaniac Tue 25-Feb-14 22:35:43

Me too! grin

EdithWeston Tue 25-Feb-14 22:36:51

Say that the number watching BBC2 is x.

The number watching BBC1 is four times as many, 4x.

And the number watching ITV is twice that, 4x x 2 = 8x

So all together x + 4x + 8x = 310

Simplify 13x = 310
At which point you have to dissect some children.

Could it be a misprint for 130 children in the school?

Then x=10.

So 10 watch BBC2, 40 BBC1 and 80 ITV.

pippibluestocking Tue 25-Feb-14 22:37:29

ITV- 184
BBC1 - 92
BBC2 - 23

TheFutureSupremeRulersMum Tue 25-Feb-14 22:38:03

Let the number of children watching BBC1 be A, BBC2 be B and ITV be C

A = 4B

C = 2A

=> C = 8B

A + B + C = 310

=> 4B + B + 8B = 310

B = 310/ 13

Agree with Edith, is there a misprint?

Skiingmaniac Tue 25-Feb-14 22:38:23

It doesn't work as if
24 kids watch bbc2
96 kids watch bbc1
192 kids watch itv

Adds up to 312confused

LineRunner Tue 25-Feb-14 22:40:10

Edith's right. It does not compute.

hercules1 Tue 25-Feb-14 22:40:47

Dh and I have been trying for ages. Dd is long gone to bed! We got to the 13 parts bit and think there must be a mistake.

MoreBeta Tue 25-Feb-14 22:40:56

Yes I agree with all above its a misprint.

The number has to be divisible by 13.

YarnyStasher Tue 25-Feb-14 22:41:13

Bbc1 = a
Bbc2 = b
Itv = c

a = 4b
c = 2a
c = 8b

a + b + c = 310
4b + b + 8b = 310
13b = 310

But that gives you a number for b that isn't a whole number, so either I'm wrong or the question is.

pippibluestocking Tue 25-Feb-14 22:41:14

It's not a misprint. Add up all the proportions (8+4+1=13) and divide 310 by 13 and then multiply up by the proportions, so for itv, it's 13x8, for BBC1, it's 13x4 & for BBC2, it's 13x1

YarnyStasher Tue 25-Feb-14 22:42:41

But you can't have .84 of a child, Pippi.

LineRunner Tue 25-Feb-14 22:42:42

Pippi, that doesn't add up to 310 though.

MoreBeta Tue 25-Feb-14 22:44:03

pippi - 310/13 =23.846

The BBC 2 viewers cant be 1/13th. Surely?

LineRunner Tue 25-Feb-14 22:44:04

Ah well, another ten minutes of my life I'll never get back because of school worksheet maths.

pippibluestocking Tue 25-Feb-14 22:44:32

Sorry, my mistake, it's 310 Divided by 13 = 23, so for ITV is 8x23, BBC1is 4x23 and so on

hercules1 Tue 25-Feb-14 22:44:35

We wondered whether it was something to do with not all the children watching TV but it doesn't tell you how many children didn't watch.

EdithWeston Tue 25-Feb-14 22:44:39

The trouble with that, pippibluestocking is that 310/13 = 23.85, so the pupils would need to be cut into pieces.

LineRunner Tue 25-Feb-14 22:46:37

If 11 children were playing x-box, pippi would be very happy.

lisad123everybodydancenow Tue 25-Feb-14 22:47:19

Message withdrawn at poster's request.

pippibluestocking Tue 25-Feb-14 22:47:50

God you're right, ignore me!!

LineRunner Tue 25-Feb-14 22:48:17

grin

Nocomet Tue 25-Feb-14 22:48:24

It doesn't work.

We agreed on Sunday you can't chop up children!

We don't have a people carrier so I said 2.5 DCs had to go in me and DHs cars. The assembled girls refused to oblige, 3&2 was their best offer grin

EdithWeston Tue 25-Feb-14 22:50:29

I suppose it could be pippi's answer, plus 11 children doing their maths homework...

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