試題詳解

128. In a group of 25 factory workers, 20 are low-risk and five are high-risk.
Two of the 25 factory workers are randomly selected without replacement.
Calculate the probability that exactly one of the two selected factory workers is low-risk.
(A) 0.160
(B) 0.167
(C) 0.320
(D) 0.333
(E) 0.633