Problem:
Two dice are thrown. What is the probability that the product of the two numbers is a multiple of
Answer Choices:
A.
B.
C.
D.
E.
Solution:
There would be entries in the table if it were complete, but only the entries that are multiples of are shown. The probability of getting a multiple of is .
Probability questions are sometimes answered by calculating the ways the event will NOT happen, then subtracting. In this problem the and faces are paired to create number pairs whose product is NOT multiples of . This leaves ways to get a multiple of , so the probability is .
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions