求助: gwd5-2,11

Q2:

What is the ratio of the average (arithmetic mean) height of students in class X to the average height of students in class Y?

(1)    The average height of the students in class X is 120 centimeters.

(2)   The average height of the students in class X and class Y combined is 126 centimeters.

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: E

这道题我觉得是自己意思理解错了,x的average知道了,x+y的average也知道了,那x/y怎么会不知道?希望G友帮忙解答下.不胜感激

Q11:

A certain business produced x rakes each month form November through February and shipped x/2 rakes at the beginning of each month from March through October.  The business paid no storage costs for the rakes from November through February, but it paid storage costs of $0.10 per rake each month from March through October for the rakes that had not been shipped.  In terms of x, what was the total storage cost, in dollars, that the business paid for the rakes for the 12 months form November through October?