Aptitude Question

In a group of 70 people, 37 like coffee, 52 like tea and each person likes at least one of the two drinks. How many people like both coffee and tea?

	a. 29
	b. 19
	c. 55
	d. 15
	e. 51

Explanation: Let A and B denote the sets of people who like coffee and tea respectively. Then by inclusion-exclusion principle, number of people who like both coffee and tea = number of people who like coffee + number of people who like tea - number of people who like either coffee or tea = 37+52-70=19.