If the average (arithmetic mean) of a and b is 110, and the average of b and c is 160, what is the value of a-c ？（）

单项选择题In the figure above, is AB＞BC ？（）(Note: Figure not necessarily drawn to scale.) (1) AB＞CD (2) (AD-AB)＞(AD-BC)

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.

单项选择题The pilot of a small aircraft with a 40-gallon fuel tank wants to fly to Cleveland, which is 480 miles away. The pilot recognizes that the current engine, which can fly only 8 miles per gallon, will not get him there. By how many miles per gallon must the aircraft’s fuel efficiency be improved to make the flight to Cleveland possible ？（）

A. 2
B. 4
C. 12
D. 40
E. 160