What is the total number of 4-digit combinations that can be formed using the digits 3, 5, 7, and 9 with repetition allowed?

Correct answer marked below

4^4

Correct

4^4-4

4^4-4^2

4^4-4^3

4^3

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Explanation

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Official Explanation

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To find the number of 4-digit combinations using the digits 3, 5, 7, and 9 with repetition, we can use the formula

4^4

. This is because…

Comments

RheaFeb 15, 2025

thanks for the answer

DEBRUPNov 3, 2024

Thanks for sharingThank you for sharing!!thanks for sharing

BatmanFeb 19, 2025

Thank you very much!

What this question tests

Whether you can count arrangements and selections correctly — permutations vs. combinations.

Overcounting: treating a selection as ordered when order does not matter, or forgetting to divide by duplicates.