If the password consists of 4 letters chosen from A-Z and it must include at least one vowel, how many possible passwords can be generated?
Category: Brain · Difficulty: hard
Hint: Consider the total combinations and then exclude those without vowels.
Answer
456976
Explanation
Total combinations are 26^4 = 456976. The total without vowels (21 consonants) is 21^4 = 194481. Subtracting gives the total with at least one vowel.
This is a hard brain riddle — a tricky one that takes a little thought. The answer is 456976.
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