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 大家帮忙谢谢
to get 5 and maintain a sum of 8, you need either (3, 5) or (5, 3) for the two draws = 2 ways total # of ways to draw the 2 cards with sum of 8: (2, 6), (3, 5), (4, 4), (5, 3), (6, 2) = 5 ways
