Answer:
In sequence: 6, 8, 12 and 16
Explanation:
Ok, the Venn diagram has 4 sections:
A - Juniors, but excluding girls (so boys only)
B - Juniors, who are also girls (so girls only)
C - Girls only, who aren't Juniors
D - Then outside the circles, for those who are not juniors and who are not girls (senior boys).
So, in A, you place the junior boys (6)
in B, you place the junior girls (8)
in C, you place the senior girls (12)
and in D, you place the senior boys (16)