Class 11MathematicsPermutation and CombinationDefinition of permutation, Number of permutations with or without repetition, Conditional permutations
Difficult$_{n-1}P_r + r \cdot (_{n-1}P_{r-1}) = \dots$
- A$_nP_r$
- B$_{n-1}P_r$
- C$_nP_{r-1}$
- D$2 \cdot _nP_r$
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