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 parents. The probability that the selected group of children have no blood relations, is equal to
Answer & explanation
Correct answer: option 3
Probability that the boy and his sister both are selected $=\frac{{ }^8 C_1}{{ }^{10} C_3}=\frac{1}{15}$
Thus, required probability = $1 - \frac{1}{15} = \frac{14}{15}$