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How many four letter words can be formed from the letters of ROSE if the letters may be repeated?
ATwenty four
BSixty four
CTwo fifty six
DOne hundred
Answer & Solution
Correct answer: C. Two fifty six
1. With repetition allowed each of the four places has all 4 letters available.
2. So the count is 4 multiplied by itself four times.
3. That is 4 raised to the fourth power, which equals 256.
_Source: NCERT Class 11 Mathematics, Ch 6 'Permutations and Combinations'_
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