This is confusing, please help

Question

How many codes with five letters can be made from the letters of
D R A G O N F L Y
if the first and last letters have to be vowels and each letter can only be used at most once?

 

 

*210
*840
*240
*420
*None of the above

Answer 1

from DRAGONFLY we have only two vowels, A and O (normally Y is not considered one of the five vowels).

 

There are two ways to place vowels: either A at front, O at end, or vice versa.

The remaining three positions can be filled in 7P3 = 210 ways.

 

ANSWER: 420.