Question
Question: Number of ways in which the candidates A<sub>1</sub>, A<sub>2</sub>, A<sub>3</sub>,……., A<sub>10</su...
Number of ways in which the candidates A1, A2, A3,……., A10 can be ranked such that A1 and A10 are never next to each other is
A
8 x 9!
B
10 x 9!
C
8 X 8!
D
None of these
Answer
8 x 9!
Explanation
Solution
Number of ways of ranking without restriction = 10!
Number of ways of ranking when A1 and A10 are next to each other = 2 x 9!
Required ways = 10 ! – 2 x 9 ! = 10 x 9! – 2 x 9! = 8 x 9!