Question 391827
Do this case by case.


Case 1: The three men serve together.
Then, there are only two people left to choose out of a group of 7, so 7C2, or 21 ways to choose two more people given this case.


Case 2: The three men don't serve.
Then, we choose 5 people out of the remaining 7, so 7C5, also equal to 21 ways (since nCr = nC(n-r), which can easily be shown algebraically).


Therefore the total number of ways is 21+21, or 42.