How many 3-letter "words" can be formed from the standard 26-letter alphabet, if the first letter must be a vowel (A, E, I, O, or U)? (We aren't necessarily talking about English words; something like EQX is perfectly valid here.)
Check out geno's great answer to this here: https://web2.0calc.com/questions/help-me-when-you-can
Hope this helped!!!