求解：一道像JJ37题的GWD数学

snowlemon

这个题目是一个CDER 从GWD 翻出来的，这个怎么做呢？
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.

shuxuehai

I would choose E.

Combining 1 and 2, we could obtain

(S+5)/(v+10)<0.5

therefore, S<V/2, it means that only under the condition that S<V/2 could we obtain (S+5)/(v+10)<0.5, but the evidence is not provided.