試題詳解

25. The probability that a randomly chosen male has a blood circulation problem is 0.25. Males who have a blood circulation problem are twice as likely to be smokers as those who do not have a blood circulation problem.
Calculate the probability that a male has a blood circulation problem, given that he is a smoker.
(A) 1/4
(B) 1/3
(C) 2/5
(D) 1/2
(E) 2/3