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.
What is the area of square floor X ？（）
(1) The perimeter of the floor is a whole-number multiple of 10.
(2) The diagonal of the floor measures 
.
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 is insufficient because the perimeter could be 10, 20, 30, and so on. (2) alone is sufficient, because the diagonal of a square, which cuts the square into two 45-45-90 triangles, will be the length of a side times 
. Thus, if the diagonal equals 
, then the sides are each 5 in length, and the area then is the square of the side, or 25.