4 -letter "words" are formed using the letters A, B, C, D, E, F, G. How many such words are possible for each of the following conditions?

Question

(a) No condition is imposed.
Your answer is :
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(b) No letter can be repeated in a word.
Your answer is :
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(c) Each word must begin with the letter A.
Your answer is :
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(d) The letter C must be at the end.
Your answer is :
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(e) The second letter must be a vowel.
Your answer is :
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Answer 1

a) no condition: 7x7x7x7 = 7^4 = 2401

b) no repeats: 7x6x5x4 = 840

c) begin with A, can I repeat the others ?
I will assume I can:
1x7x7x7 = 343

d) same as c)
7x7x7x1 = 343

e) 2nd letter is a vowel
7x2x7x7 = 686

In c), d) and e) I assumed that letters can be repeated, you did not say otherwise.
If they cannot be repeated , it is easy to change the calculations

Answer 2

Thank you! I was able to do A & B but c,d,& e I would figure out. thanks again

Answer 3

For some particular website, the password must start with the letter X. Then there must be 5 more characters, and each of those characters may be a numeric digit or a letter of the alphabet. How many different passwords are possible?