I think what turned you off about this question was the fact that you are not given a number for the actual population. However, since you are not being asked for an actual number, you are being asked for a percentage, you can just pick a number. Regardless of what number you choose, you will still end up with the same percentages.

Let's say you have a population of 1000.

The first statement tells you that there are 113 people 65 or older. Not sufficient.

The second statement tells you that 20 percent of the men and 10 percent of the women are employed. Again, not sufficient.

When you take the two together, it is sufficent. Say there are 56 men and 57 women. There are 11 men and 6 women employed. 17 out of 113 is 15%. I can now tell you - from merely doing so many percentage problems, if you try any combination of men and women, you will still end up with at least 10 percent of the 65 or over population employed. Try it for 1 man and 112 women, you are still going to end up with at least 10 percent.