SOLUTION: 4. How many 3-letter code words are possible using the first 8 letters of the alphabet if a) No letter can be repeated ? b) Letters can be repeated ?

Algebra ->  Permutations -> SOLUTION: 4. How many 3-letter code words are possible using the first 8 letters of the alphabet if a) No letter can be repeated ? b) Letters can be repeated ?       Log On


   

Question 761742: 4. How many 3-letter code words are possible using the first 8 letters of the alphabet if
a) No letter can be repeated ?
b) Letters can be repeated ?
Answer by ramkikk66(644) About Me  (Show Source):
You can put this solution on YOUR website!
Using ABCDEFGH
a) If no letter can be repeated:
First letter of he 3 letter combo can be chosen in 8 ways.
Second letter can be chosen only in 7 ways (because you can't repeat the 1st letter)
Third letter can be chosen in 6 ways.
So, total number of combinations = 8%2A7%2A6+=+336
b) If letters can be repeated, each letter of the combination can be chosen in 8 ways, so the number of combinations is 8%2A8%2A8+=+512
:)