How many different 2-digit numbers can be made using the digits 3, 7, 8, 9, 2?

1 Answer
Jul 15, 2016

#25# if the digit can be repeated.
#20# if the digits must be distinct.

Explanation:

There are #5# choices for the first digit.

If the digits can be re-used there are also #5# choices for the second digit
giving #5xx5=25# possible combinations.

If the digits can not be re-used there are only #4# choices for the second digit
giving #5xx4=20# possible combinations.