A local community has two newspapers: the morning tomes and the evening dispatch. The morning times is read by 45% of the households.  The Evening Dispatch is read by 60% of the households.  Twenty percent of the households read both papers.  What is the probability that a particular household reads at least one paper?

A.

0.45

B.

0.65

C.

0.85

D.

0.95

Correct answer is C

Note that the group that reads both papers is being counted twice.

    (percentages add up beyond 100%)

Let M = those reading the Morning Times,

       E = those reading the Evening Dispatch

P( M or E) = P(M) + P(E) – P(M and E)

          = 0.45 + 0.60 – 0.20 

          = 0.85