Number theoryDifficulty 3.0AMC 10/12Find the answerUnited Kingdom
Sonia wants to write a positive five-digit integer whose digits are 1, 2, 3, 4 and 5 in some order. The first digit of the integer is to be divisible by 1, the first two digits are to form a two-digit integer divisible by 2, the first three digits are to form a three-digit integer divisible by 3, the first four digits are to form a four-digit integer divisible by 4 and the five-digit integer itself is to be divisible by 5. How many such five-digit integers could Sonia write?
(A) 10 (B) 5 (C) 2 (D) 1 (E) 0
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