Products and divisibility

The product of any 5 consecutive positive integers must be divisible by which of the following numbers?

All of 2, 3, 4, 5, 6 2 only 3 only 4 only 5 only 6 only

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2 solutions

Eric Kim
Dec 6, 2016

In a list of consecutive numbers; every other number is divisible by 2, every 3rd number is divisible by 3, and etc.

Thus, the product of 5 consecutive integers has at least 1 factor of 2, 3, 4, and 5.

Being divisible by 2 and 3 also means the number is divisible by 6

In general, the product of n consecutive positive integers is divisible by n ! n! (n factorial).

Can you justify this? I don't think this statement alone would satisfy someone who got the problem wrong and is reading the answers for clarification.

Jason Dyer Staff - 4 years, 6 months ago

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