2019 AMC 10 A

Complete problem set with solutions and individual problem pages

Problem 2 Easy

What is the hundreds digit of (20!-15!)? (2019 AMC 10A Problem, Question#2)

  • A.

    0

  • B.

    1

  • C.

    2

  • D.

    4

  • E.

    5

Answer:A

The last three digits of n! for all n\geqslant15 are 0,because there are at least three 2\text{s} and three 5\text{s} in its prime factorization. Because 0-0=0,the answer is 0.

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