单选题 Helen Pedersen has all her money invested in either of two mutual funds (A and B). She knows that there is a 40 percent probability that fund A will rise in price and a 60 percent chance that fund B will rise in price if fund A rises in price. What is the probability that both fund A and fund B will rise in price?

A、

A. 0.24.
B、

B. 0.40.
C、

C. 0.70.

【正确答案】 A

【答案解析】P(A) =0.40, P(B|A) =0.60. Therefore, P(AB) =P(A)P(B|A) =0.40×0.60=0.24.