Mikey from Archibishop of York C of E Junior School thought hard about this problem. He says:Using the bar graph for class $4$ gives $36$ pupils but this allows several possible answers:
Well done, Mikey for seeing that there are several possible solutions - not many of you realised this. What answers are possible then? Might some be more likely than others do you think?
Lizzi from Bampton C of E Primary School wrote:By looking at the amount of pupils in class $4$ on the bar graph, you can tell that the big people on the graph equal $6$ and the little people equal $3$ people, so therefore there are $42$ people in class $7$, $39$ people in class $6$ and $30$ people in class $5$ which equals $111$ pupils.
This is certainly one of the possibilities. Freddie from Whitehall Primary School calculated another one:Big people = $7$
Joshua from BMGS suggests:... for each big figure it was $8$ and for each small one it was $1$. Then it was a simple solution of adding up all of years $5, 6$ and $7$. The total answer was $115$.
We are still left without the solution for a big stickman representing $5$ children and a small stickman representing $4$ children, but thank you for all your contributions .