In a group of 100 people,50 like reading books,20 like both reading books and listening songs. How many like listening songs?  Choices:
A) 40
B) 50
C) 70
D) 60
E) none

Rationale: make a venn diagram , and enter your data . let the number of people who like listening songs be x x + 20 + 30 = 100 x = 50 so number who like listening songs = 20 + 50 = 70 answer c
Answer: C