There are 4 possibilities for inviting the relatives to the party: 3 ladies from the husband's side and 3 gentlemen from the wife's side: Total number of ways: =‌4C3×‌4C3=16 3 gentlemen from the husband's side and 3 ladies from the wife's side: Total number of ways: =‌3C3×‌3C3=1 2 ladies and 1 gentleman from the husband's side and 2 gentlemen and 1 lady from the wife's side: Total number of ways: =(‌4C2×‌3C1)×(‌3C1×‌4C2)=324 1 lady and 2 gentlemen from the husband's side, and 2 ladies and 1 gentleman from the wife's side: Total number of ways: =(‌4C1×‌3C2)×(‌3C2×‌4C1)=144 The total number of ways to invite 3 of the man's relatives and 3 of the wife's relatives is: =16+1+324+144=485