Class 11MathematicsPermutations and CombinationsDefinition of permutation, Number of permutations with or without repetition, Conditional permutations
EasyIf $_{12}P_r = 1320$,then $r = ..........$
- A$5$
- B$4$
- C$3$
- D$2$
Explore More
Similar Questions
If ${}^9P_5 + 5 \cdot {}^9P_4 = {}^{10}P_r$, then the value of $r$ 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 $25$?
The number of all $8$-digit odd numbers is
Find the number of arrangements of the letters of the word $BANANA$ in which the two $N$'s do not appear together.
Medium
View SolutionThe total number of words that can be formed by using all the letters of the word $ALLEN$ such that all vowels occur in alphabetical order is:
Difficult
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