Question

A recent survey of Financial Post (FP) readers reported that 40% of their subscribers regularly read the Wall Street Journal (WSJ), 32% read Time (T), and 11% read both the WSJ and T. What is the probability that a randomly selected reader reads WSJ or T or both?

Answer 1

solution

Let the probability that a person reads WSJ be $P(w)=0.4$ , the times be $P(t)=0.32$ and that they read both be $P(w \cap t) = 0.11$

The probability that a person reads WSJ, times or both is: $P(w\ \cup\ t)$

From set theory,

$$P(w\ \cup\ t) = P(w)\ +\ P(t)- \ P(w\ \cap \ t)$$

$$0.40+0.32-0.11=0.61$$

answer: 0.61