Răspuns:
nr total de baieti
|____|____|____|____|____|
baieti care joaca sah
|____| 1/5
rest1 |____|____|____|____|
baieti care joaca footbal
|____|____| 1/2
rest2 |__|__|__|__|
baieti care joaca volei
|__| 1/4
rest3 |__|__|__| 42 baieti care joaca tenis
42:3 = 14 (baieti care joaca volei)
14×4 = 56 ( rest2)
56 (baieti joaca footbal)
56:2 = 28 (baieti care joaca sah)
28×5 = 140 ( baieti in total)
Verificare:
14+56+28+42 = 140