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jmc

counting and probability junior

Problem

A pair of 8-sided dice have sides numbered 1 through 8. Each side has the same probability (chance) of landing face up. The probability that the product of the two numbers that land face-up exceeds 36 is
(A)
(B)
(C)
(D)
Solution
There are combinations to examine. If one die is , then even with an on the other die, no combinations will work. If one die is , then even with an on the other die, no combinations will work. If one die is , then even with an on the other die, no combinations will work. If one die is , then even with an on the other die, no combinations will work. If one die is , then the other die must be an to have a product over . Thus, works. If one die is , then the other die must be either or to have a product over . Thus, and both work. If one die is , then the other die can be or to have a product over . Thus, , , and all work. If one die is , then the other die can be or to have a product over . Thus, and work. There are a total of combinations that work out of a total of possibilities. Thus, the answer is , and the answer is But this may be slightly complicated, so you can also do solution 2 (scroll to bottom).
Final answer
A