Question 358137
a) The first letter must be Y
Since there only 4 letters free to be chosen, the answer = 4!=24
==
b) The vowels and consonants alternate,beginning with a consonant 
-
let C=consonant, V=vowel
There are 3 C and 2 V

CVCVC 
Number of ways   3*2*2*1*1=12