Using the letters A and B, the following two-letter code words can be formed: AA, AB, BB, BA. Using the letters A, B, and C and D, how many different four-letter code words can be formed?

Guest Aug 13, 2021

#1**+1 **

*Using the letters A, B, and C and D, how many different four-letter code words can be formed?*

This would be the permutation of 4 things taken 4 at a time, abbreviated 4P4 in math.

There are 4 choices for the 1st letter,

There are 3 choices for the 2nd letter,

There are 2 choices for the 3rd letter,

There remains 1 choice for the 4th. The total number is **24**.

_{.}

Guest Aug 13, 2021