How many three-letter "words" can be made from 4 letters "FGHI" if repetition of letters

(b) is not allowed?
There are _____ possible three-letter "words"

"Probability and Counting"

How many threeletter words can be made from 4 letters FGHI if repetition of letters b is not allowed There are possible threeletter words Probability and Counti class=