SORRY !! i didn't see the read before posting.. okay heres what i did
I do not like this question because there is some ambiguity about whether Y is to be considered a vowel or a consonant. Only when you get to the last question is it clear that Y is to be considered a consonant.
a) i did 7P4 which gave me 840 words Looks good to me.
b) i multiplied 5*4*3*2 Your answer is correct if Y is considered a consonant.
c) im not sure about this one but i 5^2*4^2 Your answer is correct if Y is considered a consonant.
d) i just put 2*6*5*4 Your answer is correct if Y is considered a consonant.
e) i just multiplied 1*6*5*4 since it needs to contain letter Y This is wrong. The 6 * 5 * 4 is the number of ways that the three other letters can be chosen. But Y can go in the first, second, third, or fourth position. So for EACH distinct triplet of non-Ys, there are four ways to insert the Y. 4 * 6 * 5 * 4 = 480.
f) multiplied 1*5*4*2 right? Your answer is correct if Y is considered a consonant.
g) is it just 1*1*5*4? This is wrong. The first position is taken by T. So you have three positions to consider. One of those postions is filled with an S. So there are only two letters to be chosen out of five remaining. That gives you your 5 * 4. But the S can go in any one of three positions.
So 3 * 5 * 4.
h) i don't understand this one Oh you understand it; you just are unsure of how to do it.
i know that its easier to do indirect method i have to subtract total and no vowels ad got 720 words?