The manager of Ardmore Pharmacy knows that 25 percent of the customers entering the store buy prescription drugs, 65 percent buy over-the-counter drugs, and 18 percent buy both types of drugs. What is the probability that a randomly selected customer will buy at least one of these two types of drugs?

Question

Quizplus · Accepted Answer

We can use the formula:

P(A or B) = P(A) + P(B) - P(A and B)

where A is the event of buying prescription drugs and B is the event of buying over-the-counter drugs.

Using the information given, we have:

P(A) = 0.25, P(B) = 0.65, P(A and B) = 0.18

Therefore,

P(at least one type of drugs) = P(A or B) = P(A) + P(B) - P(A and B) = 0.25 + 0.65 - 0.18 = 0.72

So the probability that a randomly selected customer will buy at least one of these two types of drugs is 0.72 or 72%. Therefore, the best choice is C.

The Manager of Ardmore Pharmacy Knows That 25 Percent of the Customers