Hey there!
For a), there are two different ways you could do this;
i) considering the complement (total number of ways - both women in)
ii) going case by case
Method 1: Total number of ways = 7C4 x 8C3 (hopefully self explanatory)
Both women in: 2C2 (to get both women in) x 6C1 (for the other woman) x 7C4 (for the men)
= 1750.
Method 2: The cases are going to be when one woman serves, or neither woman serves.
When one woman serves: 2C1 (pick one of the women) x 6C2 (for the rest of the women, omitting the other one) x 7C4 (for the men)
When neither woman serves: 6C3 (for the women, omitting the two) x 7C4 (for the men)
Add them up, you should have 1750.
For part b), just use your answer from a), and divide by the total number of ways (outlined in method 1.) Answer should be 25/28
Hope this helps