A brother and sister appear for an interview against two vacant posts in an office. The probability of the brother's selection is 1/5th and that of the sister's selections is 1/3rd. What is the probability that one of them is selected?
Correct Answer: 1/3
Explanation:
One of them can be selected in the following ways.
Brother is selected and sister is not selected.
or
Brother is not selected and sister is selected. ∴ Required probability = 1/5 x 2/3 + 4/5 x 1/3
= 2/15 + 4/15 = 6/15 = 2/5
