第1个回答 2011-08-10
(1)任取2张卡片,可能的情况为:01,02,03,04,12,13,14,23,24,34
数字之和为4的有:04,13。所以概率=1/5
(2)这一次的情况有:00,01,02,03,04,11,12,13,14,22,23,24,33,34,44
和为4的有:04,13,22,所以概率=1/5
第2个回答 2011-08-10
(1) 可能会是 0 1,02,03,04,10,12,13,14,20,21,23,24,30,31,32,34,40,41,42,43,和是1,2,3,4,1,3,4,5,2,3,5,6,3,4,5,7,4,5,6,7,和是4的概率1/5
(2) 00,01,02,03,04,10,11,12,13,14,20,21,22,23,24,30,31,32,33,34,40,41,42,43,44,和是0,1,2,3,4,1,2,3,4,5,2,3,4,5,6,3,4,5,6,7,4,5,6,7,8,5,6,7,8,9 也是1/5