Question

how many players are there in all?

Answer 1

Let A, B, and C be the sets of players forming kabaddi, kho-kho, and football teams, respectively. Then
$n\left(A\right)=21$, $n\left(B\right)=26$, $n\left(C\right)=29$, $n(A\cap B)=14$,
$n(A\cap C)=12$, $n(B\cap C)=15$ and $n(A\cap B\cap C)=8$.
$n(A\cup B\cup C)=n\left(A\right)+n\left(B\right)+n\left(C\right)-n(A\cap C)-n(B\cap C)-n(A\cap C)+n(A\cap B\cap C)$
$=21+26+19-14-12-15+8=43$