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