您好，问题如下，有些冗长不好意思
Q: A pair of dice, one red and the other green, is rolled six times. We know
that the ordered pairs (1, 1), (1, 5), (2, 4), (3, 6), (4, 2), (4, 4), (5,
1), and (6, 3) did not come up. What is the probability that every value came
up on both the red die and the green one?
A:
题目说掷六次中，红色和绿色的点数{1, 2, 3, 4, 5, 6}都要出现。理解为这是A->B
一对一对的关系，但是又要扣掉禁位的pairs。
所以这是这是红绿骰子的禁位表格
a1 表示出现点数对(1, 1)(1, 5)
a2