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？ | 
