I am stuck on my sons maths homework.please help

3 adults, 50 kids, 47 pensioners

Must have been a good film 

100 Pensioners no adults and no kids.

Assuming that there x Adults, y Pensioners and z Children, we get two equations:
(1) x + y + z = 100, and
(2) 350x + 100y + 85z = 10000 on converting pounds to pence.

Now divide second equation by 5 to get:
70x + 20y + 17z = 2000
and multiply first equation with 20 to get:
20x + 20y + 20z = 2000

On subtracting, we get
50x - 3z = 0

As Adults, Pensioners and Children can be whole number and all audience are not pensioners. So, x or z need to be greater than zero.
Therefore x=3 and z =50 and y = 47

https://wild.maths.org/going-cinema

Sorry just read question again.

no point in converting to pence, leave as £, that way you can immediately subtract the 2 equations to leave the adult/kid ratio

Not everyone is a pensioner could mean that 100 people paid pensioner rates but some of them were adults that chanced getting OAP rates and didn't get asked for ID

8 and a half pence ?

Llemedos does not you table show £100.45??

Sorry you are correct didnt  realise you switched y & z

not everyone is a pensioner.how many adults ,kids and pensioners are present.?

Poorly worded question.

Why does there have to be any kids?

If 0 kids its easy.

3 adults = £10.5
50 kids =£42.5
47 pensioners = £47

100 people
100 pound

Why does there have to be any kids?
If 0 kids its easy.

No solution if no kids.