Question

Arjith and Karan sit in a ring arrangement with 10 persons. What is the probability that Arjith and Karan will sit together?

• A. 2/11
• B. 3/11
• C. 7/11
• D. 5/9
• E. none

Answer 1

The correct option is A

2/11

n(S)= number of ways of sitting 12 persons at round table:
=(12−1)!=11!

So, 11 persons will be seated in (11−1)!=10! ways at round table and 2 particular persons will be seated in 2! ways.

n(A) = The number of ways in which two persons always sit together =10!×2

P(A) $=\frac{n\left(A\right)}{n\left(S\right)}=\frac{2}{11}$