标题: 求解OG 2018 DS 380题 完全不理解 多谢各位！ [打印本页] 作者: Lynn07 时间: 2017-10-8 10:35 标题: 求解OG 2018 DS 380题 完全不理解 多谢各位！ 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.