Question

how many ways are there to write a 3 digit positive number integer using the digits 1,3,5,7, and 9 if no digit is used more than once

Answer 1

Answer: 60

Explanation:

To form a 3-digit positive integer using the digits 1, 3, 5, 7, and 9 without repeating any digit, we can use the counting principle.

There are 5 choices for the first digit (hundreds place) since any of the 5 digits (1, 3, 5, 7, or 9) can be placed there.

5 (choices for the first digit) × 4 (choices for the second digit) × 3 (choices for the third digit) = 60

There are 60 ways to write a 3-digit positive integer using the digits 1, 3, 5, 7, and 9 without using any digit more than once.