Question

Three children are selected at random from a group of 6 boys and 4 girls. It is known that in this group exactly one girl and one boy belong to same parent. The probability that the selected group of children have no blood relations, is equal to

• A. $\frac{1}{15}$
• B. $\frac{13}{15}$
• C. $\frac{14}{15}$
• D. $\frac{2}{15}$

Answer 1

The correct option is C $\frac{14}{15}$

P(boyand his sister both are selected) = $\frac{8C_1}{10C_3}=\frac{1}{15}$
$\therefore$ required probability = $1-\frac{1}{15}=\frac{14}{15}$