**Question**:

**Answer**: Assumption: Each child play at least one game

Children Play Tennis = T

Children Play FootBall = F

Children Play Both = B

Just FootBall = F – B

Just Tennis = T – B

The same number play tennis as play just football

=> F – B = T

Twice as many play both tennis and football as play just tennis

2B = T – B

=> T = 3B

F – B = 3B

=> F = 4B

Total = T + F – B = 42

=> 3B + 4B – B = 42

=> 6B = 42

=> B = 7

T = 3B = 21

F = 4B = 28

FootBall = 28

Tennis = 21

Both = 7

Just Football = 21

Just Tennis = 14

28 children play football