Q.

Relatives of a man comprise 4 ladies and 3 gentlemen, and his wife has also 7 relatives: 3 of them are ladies and 4 gentlemen. In how many ways can they invite a dinner party of 3 ladies and 3 gentlemen so that there are 3 of the man's relatives and 3 of the wife's relatives


Ans.

(485)

3 gentlemen and 3 ladies may be chosen as follows:

Case Man Wife
Case I 3(L) 3(G)
Case II 2(L), 1(G) 2(G), 1(L)
Case III 1(L), 2(G) 2(L), 1(G)
Case IV 3(G) 3(L)

Required number of ways of inviting 3 ladies and 3 gentlemen to the party

=C34×C34+(C24×C13)(C13×C24)+(C14×C23)(C23×C14)+C33×C33

=16+324+144+1=485