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Question:

Two newspapers A and B are published in a city. It is known that 25% of the city population reads A, 20% reads B, and 8% reads both A and B. What percentage of the population reads at least one of the newspapers?

13.9

13.5

13

12.8

Solution:

The correct option is C (13.9)
Let population = 100
n(A) = 25; n(B) = 20; n(A∩B) = 8; n(A∩B') = 17; n(A'∩B) = 12
30/100 * 17 + 40/100 * 12 + 50/100 * 8
5.1 + 4.8 + 4 = 13.9