試題詳解

127. In a group of health insurance policyholders, 20% have high blood pressure and 30% have high cholesterol. Of the policyholders with high blood pressure, 25% have high cholesterol.
A policyholder is randomly selected from the group.
Calculate the probability that a policyholder has high blood pressure, given that the policyholder has high cholesterol.
(A) 1/6
(B) 1/5
(C) 1/4
(D) 2/3
(E) 5/6