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.
How many more dogs than cats are in the veterinarian’s office ？（）
(1) There is a total of 30 dogs and cats in the office.
(2) The number of cats is the square root of the number of dogs.
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：C
解析：
Statement (1) alone is insufficient because it does not give the breakdown between dogs and cats of the 30 animals. Statement (2) alone is insufficient because the pair of numbers described could be 2 and 4, 3 and 9, 4 and 16, and so on. When the two statements are combined, however, there is only one pair of numbers that can match both statements: 5 and 25. That is sufficient information to answer the question.