Class 11MathematicsPermutation and CombinationDefinition of permutation, Number of permutations with or without repetition, Conditional permutations
DifficultThree persons enter a lift at the ground floor. The lift goes up to the $10^{\text{th}}$ floor. If the lift does not stop at the $1^{\text{st}}$, $2^{\text{nd}}$, and $3^{\text{rd}}$ floors, the number of ways in which the three persons can exit the lift at three different floors is equal to . . . . . . .
- A$210$
- B$420$
- C$105$
- D$315$
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