Find the number of ordered triples of divisors of 360 such that is also a divisor of 360.
Solution
Since , the only possible prime divisors of are 2,3 , and 5 , so we can write , for nonnegative integers , and . Then, if and only if the following three inequalities hold. Now, one can count that there are 20 assignments of that satisfy the first inequality, 10 assignments of that satisfy the second inequality, and 4 assignments of that satisfy the third inequality, for a total of 800 ordered triples .
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