Class 11MathematicsPermutation and CombinationDefinition of permutation, Number of permutations with or without repetition, Conditional permutations
EasyIf $^n{P_5} = 9 \times {^{n - 1}}{P_4}$,then the value of $n$ is
- A$6$
- B$8$
- C$5$
- D$9$
Explore More
Similar Questions
If all the letters of the word $MOST$ are permuted and the words (with or without meaning) thus obtained are arranged in the dictionary order,then the rank of the word $STOM$ when counted from the rank of the word $MOST$ is:
If four-digit numbers are formed by using the digits $1, 2, 3, 4, 5, 6, 7$ without repetition,then how many of these numbers are exactly divisible by $25$?
All possible numbers are formed using the digits $1, 1, 2, 2, 2, 2, 3, 4, 4$ taken all at a time. The number of such numbers in which the odd digits occupy even places is
DifficultJEE MAIN 2019
View SolutionIn how many ways can $mn$ letters be posted in $n$ letter-boxes?
Difficult
View SolutionHow many numbers can be formed using the digits $0, 1, 2, 3, 4, 5$ that are greater than $3000$ (repetition is not allowed)?
MediumIIT 1976
View SolutionVedclass Products
For Students
Vedclass Test Series
Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.
Start Free TrialFor Teachers
Exam Paper Generator
Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.
Try FreeFor Institutes
Online Exam Module
Live online exams with unlimited students, 360° analytics & white-label branding.
See Demo