Question

If n students are to be seated around a round table at random, the probability that two particular students will be together is

• A. $\frac{1}{n-1}$
• B. $\frac{2}{n-1}$
• C. $\frac{3}{n-1}$
• D. $\frac{4}{n-1}$

Answer 1

Answer: (B)

$\frac{2}{n-1}$

Make the bundle of those two students, Now we have $(n-1)$ students
The ways of arranging them in circle $=(n-2)!\ast 2!$
$n\left(S\right)=(n-1)!$
The required probability $=\frac{2}{(n-1)}$