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