How many different 6-letter radio station call letters can be
made
a. if the first letter must be E, W, or T and no letter may be
repeated?
b. if repeats are allowed (but the first letter is E, W, or
T)?
c. How many of the 6-letter radio station call letters (starting
with E, W, or T) have no repeats and end with the letter H?
a. If the first letter must be E, W, or T, and all...