In a population of 100 persons, 40 persons like tea and 30 persons like coffee. 10 persons like both of them. How many persons like either tea or coffee?

Correct Answer: 60
Given, a + b + c + d = 100, a + c = 40, b + c = 30, c = 10 b+10=30 => b=20 a + b + c = 40+20 = 60 i.e. 60 persons like either tea or coffee.