GWD19~Q16~概率问题~

evelyn205205

M = {-6, -5, -4, -3, -2}
T = {-2, -1, 0, 1, 2, 3}
If an integer is to be randomly selected from set M above and an integer is to be randomly selected from set T above, what is the probability that the product of the two integers will be negative?

答案是1/2。
我做出来是2/5，肯定是方法有问题了。
请NN帮忙，谢谢~