Six cards numbered from 1 to 6 are placed in an empty bowl. First one card is drawn and then put back into the bowl; then a second card is drawn. If the cards are drawn at random and if the sum of the numbers on the cards is 8, what is the probability that one of the two cards drawn is numbered 5?

A. 1/6       B 1/5      C 1/3      D 2/5    E 2/3

答案是 D

望能者帮忙

这是个条件概率的问题,前面都是骗人的

既然和是8,所以情况是:

2-6(2)

3-5(2)

4-4(1)

所以出现5的概率是2/5