SOLUTION: How many different radio stations can be named with 4 different letters of the alphabet in which "D" must come first? (Repetition is not allowed)

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Question 1194847: How many different radio stations can be named with 4 different letters of the alphabet in which "D" must come first? (Repetition is not allowed)
Answer by math_tutor2020(3817) About Me  (Show Source):
You can put this solution on YOUR website!

We have 3 slots to fill. The first slot is locked in as "D".

There are 26-1 = 25 letters to pick from for the second slot.
Then 25-1 = 24 letters for the third slot.
Finally there are 24-1 = 23 letters for the fourth final slot.
This countdown is directly due to repeated letters not being allowed.

1*25*24*23 = 13,800 different radio station names are possible.