Class 11MathematicsPermutation and CombinationDefinition of permutation, Number of permutations with or without repetition, Conditional permutations
MediumIf $^{56}P_{r + 6} : ^{54}P_{r + 3} = 30800 : 1$,then $r = $
- A$31$
- B$41$
- C$51$
- DNone of these
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