A man & his wife appear in an interview for 2vacancies in the same post. The probability of husband's selection is 1/7 & the probability of wife's selection is 1/5. What is the probability that only 1 of them is selected ?  Answers
A) 1/3
B) 2/3
C) 2/7
D) 3/11
E) 4/5
Let A = Event that the husband is selected and   B = Event that the wife is selected.   Then, P (A) = 1/7   and P(B) = 1/5   ∴P(A¯) = (1 - 17/5) = 6/7   and   = (1 - 1/5) = 4/5   Required probability = P [(A and not B) or (B and not A)]   = P[(A and B¯) or (B and A¯)]   = P(A and B¯) + P(B and A¯)   = P(A).P(B¯) + P(B).P(A¯)   = (1/7* 4/5) + (1/5* 6/7)   = 10/35   = 2/7   2/7
<result>C</result>
A man & his wife appear in an interview for 2vacancies in the same post. The probability of husband's selection is 1/7 & the probability of wife's selection is 1/5. What is the probability that only 1 of them is selected ?