Q2:

In planning for a trip, Joan estimated both the distance of the trip, in miles, and her average speed, in miles per hour.  She accurately divided her estimated distance by her estimated average speed to obtain an estimate for the time, in hours, that the trip would take.  Was her estimate within 0.5 hour of the actual time that the trip took?

(1)   Joan’s estimate for the distance was within 5 miles of the actual distance.

(2) Joan’s estimate for her average speed was within 10 miles per hour of her actual average speed.

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.

这道题居然选E，距离/速度不是等于时间吗？好奇怪，大牛指点一下，谢谢~~~

选E是对的。

因为不知道实际的距离和速度和这个估计误差范围的比例

因此误差可能大也可能小

具体带两组数字就可以了

i see,thanks !