a committe of three people are to be chosen from four married couples. how may way can this committe can be chosen if.

(a) all are equally eligible

(b) the committe must consist of 1 woman and two men

(c) all are equally eligible except that a husband and wife cannot serve on the same committe

for (a) number of ways =3x2x4 = 24

(b) $\displaystyle = \frac{n!}{(n-r)!}$

$\displaystyle =\frac{12!}{(12-3)!}$

$\displaystyle =\frac{12!}{(9)!}$

are these correct .

how would i determine (c)