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2015 AMC 10B Problem 23

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2015 AMC 10B Problem 23AMC 10 Step by Step

Name: Date: September 13, 2026

Divisibility & Factors · difficulty 4 of 5 · about 7 min · position P21-25

Let $n$ be a positive integer greater than 4 such that the decimal representation of $n!$ ends in $k$ zeros and the decimal representation of $(2n)!$ ends in $3k$ zeros. Let $s$ denote the sum of the four least possible values of $n$ . What is the sum of the digits of $s$ ?

A)
$7$
B)
$8$
C)
$9$
D)
$10$
E)
$11$

2015 AMC 10B Problem 23

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