the answer is: each school picked up 12/128 tons
if I get the graph correct, every cross indicate the quantity under it. (an x above 1/8 means that there is 1/8 of a ton collected)
then, we need to add up the total amount of tons they collected.
we have 6 crosses in 1/8, 8 crosses in 1/4 and 2 crosses in 1/2. then we do:
we add everithing:
the total amount of trash collected is 15/4 tons (3.75 tons)
there are 32 schools, then we need to divide the amount of trash by the amount of schools:
every school got 15/128 tons of trash