The part (a) of the questions was well attempted by majority of the candidates. They were able to recall that the number of ways in which 2 boys must not sit together is equal to no of ways of sitting 8 people minus no of ways if 2 boys must sit together which is
8! –(2 x 7!) = 30240 ways.
In the part (b), they were able to obtain the probability of selecting 3 men and 1 woman as 7C 3 x 3C1 = ½ and the probability of selecting at least 2 women as 10C4
7C2 x 3C2 + 7C1 x 3C2 = 1/3 or 0.333
10C4