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What is the units digit of the product of any five consecuti

by Max@Math Revolution » Fri Mar 08, 2019 1:21 am

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[GMAT math practice question]

What is the units digit of the product of any five consecutive positive integers?

A. 0
B. 2
C. 4
D. 6
E. 8
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by Max@Math Revolution » Sun Mar 10, 2019 5:03 pm
=>

Since one of the five consecutive integers must be a multiple of 5 and one must an even number, their product is a multiple of 10.
Thus, the units digits of the product is 0.

Therefore, the answer is A.
Answer: A
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by Scott@TargetTestPrep » Mon Mar 11, 2019 6:58 am
Max@Math Revolution wrote:[GMAT math practice question]

What is the units digit of the product of any five consecutive positive integers?

A. 0
B. 2
C. 4
D. 6
E. 8

Since we know that the product of 5 consecutive integers will always have prime factors of 2 and 5, the units digit of that product will always end in a zero.

Alternate solution:

Since the product of any five consecutive positive integers is divisible by 5! = 120, then the units digit of the product must be 0.

Answer: A

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