Question

Find the number of possible call letters of a radio station (7 letters long) if the first letter must be a W or a K and no letter is repeated.

Answer 1

ok, there are 7 letters total, and for the first letter we have 2 possibilities
for the second letter we have 25 possibilities since we already used one
and then we keep going until we get to the 7th letter, giving us:

2*25*24*23*22*21*20

Answer 2

oh okay