by ManhattanPrepLSAT1 Wed Oct 20, 2010 2:17 pm
Sure. This question relies heavily on the second constraint that any candidate that speaks fifth at any of the meetings must speak first at at least one of the other meetings.
So if R speaks first at meetings one and two, and S speaks first at the third meeting, then R and S are the only candidates who can speak fifth. It would look like:
R _ _ _ S meeting 1
R _ _ _ S meeting 2
S _ _ _ R meeting 3
1 2 3 4 5
Thus, it must be true that S speaks fifth at exactly two of the meetings - answer choice (E).
Does that answer your question?