SOLUTION: We have the letters A B C D E and F. How many possible three-letter codes are there if repititions are permitted and codes must contain exactly one letter A

Algebra ->  Permutations -> SOLUTION: We have the letters A B C D E and F. How many possible three-letter codes are there if repititions are permitted and codes must contain exactly one letter A      Log On


   



Question 883420: We have the letters A B C D E and F. How many possible three-letter codes are there if repititions are permitted and codes must contain exactly one letter A
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Repetitions are allowed except for the letter A.
So then it must contain one A and repetitions of the other 5 letters is OK.
The A can be in one of three locations:(AXY),(XAY),(XYA)
So we'll find the total number for one and multiply by 3.
N=1%2A5%2A5=25
3N=3%2A25
3N=75 possible codes