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In how many different ways can four-letter arrangements be formed from the letters of the word “MOTHER” such that every arrangement includes the letter M?
- 240
- 120
- 60
- 360
Correct answer: 240
Solution
MOTHER has 6 distinct letters. Words of length 4 = 6P4 = 360; those with no M = 5P4 = 120. So words containing M = 360 - 120 = 240.
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