The following data sufficiency problems consist of a question and two statements, labeled (1) and (2), in which certain data are given. You have to decide whether the data given in the statements are sufficient for answering the question. Using the data given in the statements plus your knowledge of mathematics and everyday facts (such as the number of days in July or the meaning of counterclockwise), you must indicate whether.
Is rs=rx-2 （）
(1) r is an odd number
(2) x=s+2
A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
参考答案：B
解析：
alone can neither prove nor disprove the equation above because there are infinite values of r, s, and x for which the equation could be true or false. (2) is sufficient to prove that the equation is true; restate the equation as rs=rs+2r-2; therefore, 2=2r, and r=1. If r=1, then the equation above can be simplified to s=x-2, which is the same statement as (2), which we know to be true. So (2) is sufficient.