The digits 2, 3, 4, 7, and 8 are each used once in a random order to form a five-digit number. what is the probability that the resulting number is divisible by 4? express your answer as a common fraction.

Question

Leilani Friedman

Mathematics

20 April, 13:51

The digits 2, 3, 4, 7, and 8 are each used once in a random order to form a five-digit number. what is the probability that the resulting number is divisible by 4? express your answer as a common fraction.

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Answers (1)

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Brock Bass · Answer 1

We have 5 digits. So there are: 5 * 4 * 3 * 2 * 1 = 120 five - digit numbers if we use each digit once. And : n = 120 (all incomes)

If the resulting number is divisible by 4, then the last 2-digit number must be divisible by 4: 24, 28, 32, 48, 72, or 84 (6 in total). And the first 3 digits of those numbers can be ordered in 3 * 2 * 1 = 6 ways.

m = 6 * 6 = 36 (favorable incomes)

Probability = m / n = 36 / 120 = 3 / 10.

Answer: The probability is 3 / 10.