Martin has worked for the last 30 years. If his average (arithmetic mean) total annual earnings for the first 5 years is $15,000, what is his average total annual earnings for the last 5 years? (1) Martin’s average total annual earnings for the first 25 years is $27,000. (2) Martin’s average total annual earnings for the last 25 years is $34,000. 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. Answer:

为什么选C啊？怎么做的？

条件1(1~25年的工资)和题目给的内容可以算出第6到第25年的平均工资.

根据条件2(6~30年的工资)和6~25年的平局工资可以算出最后5年的工资.

題目給了前5年的平均薪資,為條件0) 求後5年的平均薪資

條件1)給了前25年的平均薪資 >> 不充分 條件1)給了後25年的平均薪資 >> 不充分

條件1)+2) 由條件2)+0) >> 得到30年的平均薪資 加上條件1) >> 得到後5年的平均薪資

故為(C)

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