NCERT Solutions for Exercise 6.2, Class 11, Maths

Exercise 6.2
Permutations and combinations
Question and Answers
Class 11 – Maths

Class	Class 11
Subject	Mathematics
Chapter Name	Permutations and Combinations
Chapter No.	Chapter 6
Exercise	Exercise 6.2
Category	Class 11 Maths NCERT Solutions

Question 1 Evaluate

(i) 8 !

(i) 8! = 8 × 7 × 6 × 5 × 4 × 3 × 2 × 1 = 40320

(ii) 4 ! – 3 !

(ii) 4! = 1×2×3×4 = 24

3!=1×2×3 = 6

Therefore , 4! – 3!  = 24 – 6   = 18 

Question 2  Is 3 ! + 4 ! = 7 ! ?

Answer 3!=1×2×3 = 6

4! = 1×2×3×4 = 24

3! + 4! = 6 +24 =30

7! = 7 × 6 × 5 × 4 × 3 × 2 × 1 = 5040

Therefore, LHS ≠ RHS

Question 3 Compute

Answer 3 

Question 4 FInd x , if

Answer 

Question 5 Evaluate

(i) When n = 6, r = 2

=30

(ii) When n = 9, r = 5

= 9×8×7×6×5 = 15120