How many 3-letter codewords can be formed if: At least one of the letters is to be chosen from the vowels? _____ Exactly two are vowels? _____ All are consonants? ___

How many different​ 10-letter words​ (real or​ imaginary) can be formed from the following​ letters?   nbsp Upper H comma Upper R comma Upper I comma Upper B comma Upper J comma Upper I comma Upper R comma Upper I comma Upper P comma Upper Y

A string has the form 0???0, where each ? could be a 0 or a 1. How many possible strings are there? A 4 B 6 C 8 D 16

lockers to members of a baseball team. Assume that you are assigning one of 15 available lockers to each of the 5 players on the team. In how many ways can this assignment be made so that each player gets a different locker?