How many 3-letter words can we make from the letters A, B, C, and D, if we are allowed to repeat letters, and we must use the letter A at least once, and the letter B at least once?

Guest Dec 21, 2021

#1**+1 **

If a word consists of _ _ _ blanks, and A and B must be used once each,

there could be __6 different positions__. (AB{}, A{}B, BA{}, B{}A, {}AB, {}BA)

the blank has __four different values__ for each position (A, B, C, or D)

If we multiply the number of postions by what value could be filled in for each postion, we get 4x6=24

There are therefore 24 ways.

Guinevere Dec 21, 2021