作者anita7742 (歆小喵)
看板GMAT
標題[計量] GWD-13-35
時間Thu Jul 23 23:11:31 2009
Stations X and Y are connected by two separate, straight, parallel rail lines
that are 250 miles long. Train P and train Q simultaneously left Station X
and Station Y, respectively, and each train traveled to the other’s point of
departure. The two trains passed each other after traveling for 2 hours. When
the two trains passed, which train was nearer to its destination?
(1)At the time when the two trains passed, train P had averaged a speed of 70
miles per hour.
(2)Train Q averaged a speed of 55 miles per hour for the entire trip.
ans:原為C,但是在傷咖裡的討論串有人說是a？
討論串中說A理由充分的原因是因為選項說"在交會時的平均速率為70",
所以代表p已經走了140miles了
可是我的疑問是：在交會時的平均速率＝前兩小時的平均速率嗎？
如果是在交會前兩秒加速的怎麼辦？
（完了我覺得這好像跟我的理化程度有關）
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1F：推 Calla:我覺得是A吧 翻交會時的平均速率不太準確 應該說"兩台火車 07/25 00:40
2F：→ Calla:交會時 火車P的平均速率是一小時70 mi" 平均速率應該是指從 07/25 00:41
3F：→ Calla:發車交會時的平均速度 即使是交會前兩秒加速到150 題目既給 07/25 00:41
4F：→ Calla:定交會時平均速率是70 可見他之前可能速度都低於70 應該是 07/25 00:42
5F：→ Calla:這樣吧?! :D 07/25 00:42