Question

If 10 persons are to sit around a round table, the odds against two specified persons sitting together is

• A. $\frac{1}{9}$
• B. $\frac{2}{9}$
• C. $7$ to $2$
• D. $2$ to $7$

Answer 1

The correct option is C $7$ to $2$

Odd against two specified persons sitting together $=\frac{[7!\ast (2!\ast C(8,2)\left)\right]}{[9!-7!\ast (2!\ast C(8,2))}$
$=7/2$