rishianand7 wrote:If the drama club and music club are combined, what percent of the combined membership will be male?
(1) Of the 16 members of the drama club, 15 are male.
(2) Of the 20 members of the music club, 10 are male.

Clearly, neither statement alone is sufficient.
Statements combined:

Case 1: No one is a member of both clubs
Total males = 15+10 = 25.
Total members = 16+20 = 36.
Resulting fraction:
(total males)/(total members) = 25/36.

Case 2: Every male in the music club is also in the drama club, but no females belong to both.
Males in both clubs = 10.
Males in only the drama club = (total males in drama) - (males in both) = 15-10 = 5.
Total males = males in both + males in only drama = 10+5 = 15.
Total members = total music + total drama - males in both = 16 + 20 - 10 = 26.
Resulting fraction:
(total males)/(total members) = 15/26.

Since different fractions are possible, the two statements combined are INSUFFICIENT.

The correct answer is E.

Two ways to catch yourself on these kinds of problems:

1) If a Data Sufficiency question (especially on your actual exam, where the computer is adapting to you) EVER seems like an easy C, the answer is almost certainly something else, even if you can't see why at that moment. "The easy C" in DS is the most dangerous answer on the entire exam. (Well, that and "Cannot be determined" on a Problem Solving question.)

2) Whenever you have two groups with some overlap, draw a 2x2 table like this:

If you can't fill in the "Neither" box (No to one variable and No to the other), you probably won't be able to answer the question.