In a school, 300 students play cricket and 250 play hockey. If 110 students play both games, how many students play either cricket or hockey?
Answer: B
Let C be the set for cricket and H for hockey.
n(C) = 300, n(H) = 250, n(C ∩ H) = 110.
The number of students who play either game is the union, n(C ∪ H).
n(C ∪ H) = n(C) + n(H) - n(C ∩ H)
n(C ∪ H) = 300 + 250 - 110 = 550 - 110 = 440.