No of women : children = 5: 2
2) No of women < 30
so possible no of women = 5,10,15.....25
Not Suff
1) No of Children : men = 5:11
Women : Children : Men
25:10:22 cos W : C = 5:2 & C : M = 5:11
The ratios are known but not the exact nos.
Insuff
Together
it is 25 W which is < 30, 10 children & 22 Men
IMO C

We know at the start that women:children is 5:2. (1) gives us children to men, so at best this statement will allow us to find the ratio of Women:children:men. It won't give us any specific number.

(2) by itself tells us nothing about men.

When the statements are combined you must realize that because we are talking about people, we're dealing with integers. For instance, the number of women must be a multiple of 5 because the ratio of women to children reduces to 5:2. This, along with the info from (1) will allow us to achieve sufficiency. C is the correct choice.


To better understand, have a look at the video solution. This is GMATPrep question 1175

-Patrick