A and B appear for an interview for two vacancies in the same post. The probability of A’s selection is 1/6 and that of B’s selection is 1/4. Find the probability that

(i) both of them are selected


(ii) only one of them is selected


(iii) none is selected


(iv) at least one of them is selected.


Given : A and B appear for an interview ,then P(A) = and P(B) = P() = and P() =


Also, A and B are independent .A and not B are independent, not A and B are independent.


To Find: i) The probability that both of them are selected.


We know that, P( both of them are selected) = P( A B) = P(A) P(B)


=


=


Therefore , The probability that both of them are selected is


ii) P(only one of them is selected) = P(A and not B or B and not A)


= P(A and not B) + (B and not A)


= P( A ) + P(B )


= P(A) P() + P(B) P()


= + )


= +


=


Therefore, the probability that only one of them Is selected is


iii)none is selected


we know that P(none is selected) = P()


= P() P()


=


=


Therefore , the probability that none is selected is


iv) atleast one of them is selected


Now, P(atleast one of them is selected) = P(selecting only A ) + P(selecting only B) + P(selecting both)


= P(A and not B) +P (B and not A) +P (A and B)


= P( A ) + P(B ) + P( A B)


= P(A) P() + P(B) P() + P(A) P(B)


= + )+


= + +


=


Therefore, the probability that atleast one of them is selected is


1