The probability that for any married couple the husband has a degree is and the probability that the wife has a degree is . The probability that the husband has a degree, given that the wife has a degree, is A married couple is chosen at random. Find the probability that

(a) both of them have degrees,

(b) only one of them has a degree,

(c) neither of them has a degree. Two married couples are chosen at random.

(d) Find the probability that only one of the two husbands and only one of the two wives have a degree. (L)