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The number of permutations of n different objects taken r at a time, when repetition is allowed, is given by which expression?
An raised to r
Br raised to n
Cn raised to one
Dr raised to one
Answer & Solution
Correct answer: A. n raised to r
1. With repetition allowed, every one of the r places has all n objects available.
2. So each place contributes a factor of n independently.
3. Multiplying n by itself r times gives n raised to r.
_Source: NCERT Class 11 Mathematics, Ch 6 'Permutations and Combinations'_
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