Question 128730
The call letters of a radio station must have 4 letters.  The first letter must be a K or a W.
How many different station call letters can be made if repetitions are not allowed? 
# of ways to pick the 1st letter: 2 ways
# of ways to pick the 2nd letter: 25
# of ways to pick the 3rd letter: 24
# of ways to pick the 4th letter: 23
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Total # of ways: 2*25*24*23 = 27600
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And if repetitions are allowed?
# of ways to pick the 1st leter: 2 ways
# of ways to pick each of the other letters: 26
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Total # of ways = 2*26^3 = 35152
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Cheers,
Stan H.