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
(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