

Let B, H, F denotes the sets of members who are on the basketball team, hockey team and football team respectively.
Now, n(B) = 21
n(H) = 26
n(F) = 29
n(H ∩ B) = 14
n(H ∩ F) = 15
n(F ∩ B) = 12
n(B ∩ H ∩ F) = 8
We have to find the value of n(B ∪ H ∪ F)
Now,
n(B ∪ H ∪ F) = n(B) + n(H) + n(F) + n(H ∩ B) - n(H ∩ F) - n(F ∩ B) = 12 + n(B ∩ H ∩ F)
=> n(B ∪ H ∪ F) = 21 + 26 + 29 - 14 - 15 - 12 + 8
=> n(B ∪ H ∪ F) = 84 - 41
=> n(B ∪ H ∪ F) = 43
So, there are 43 members altogather.
