SOLUTION: If the call letters of radio stations must begin with the letter D, the second letter must be W, X, Y, Z while the third and fourth may be any letter how many different stations ca

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Question 1106266: If the call letters of radio stations must begin with the letter D, the second letter must be W, X, Y, Z while the third and fourth may be any letter how many different stations can there be?
a. If a repetition of letter is not allowed?
b. If repetitions are allowed?

Answer by math_helper(2461) About Me  (Show Source):
You can put this solution on YOUR website!

I assume the no repetition applies across all 4 letters of the call letters, not just the last two letters…
a) 1*4*21*20 = _______________
b) 1*4*26*26 = _______________