Both statements 1 and 2 together are sufficient to answer the questionbut neither statement is sufficient alone.
Each of the two statements is insufficient on its own. In each case, its impossible to isolate the term r-s, and each has two variables in a single linear equation. Taken together, the statements are sufficient.
Since each one is a linear equation with the variables r and s, and since they are distinct, you can solve for r and s, and then find r-s. Choice (C) is correct.
While you don.t need to actually solve for r-s to answer the question, you would do so as follows. Start by isolating r in the first equation:
