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标题: GMAT 数学提问? [打印本页]

作者: mandying    时间: 2009-12-15 07:31     标题: GMAT 数学提问?

哪位高手帮在下解解这道题~~感觉题目有问题??

A hiker walking at contant rate of 4 miles per hour is passed by a cyclist travelling in the same direction along the same path at a contant rate of 20 miles per hour, a cyclist stop to wait for the hiker 5 minutes after passing her, while the hiker continues to walk at her constant rate, how many minutes must the cyclist wait until the hiker catches up ?

答案是20minus~~~
作者: funnytigers    时间: 2009-12-15 20:35

hiker: 4miles/hour=(4/60)miles/minute,
cyclist: 20miles/hour=(20/60)miles/minute,
cyclist在经过了hiker5分钟以后停下来等她
在这5分钟里:
cyclist走了(20/60)*5=(100/60)miles
hiker走了(4/60)*5=(20/60)miles
5分钟之后,在cyclist停下来等hiker的时候:
hiker和cyclist之间的距离是(100/60)miles-(20/60)miles=(80/60)miles
(80/60)miles除以hiker的速度(4/60)miles/minute,就得出cyclist需要等待的分钟数,也就是hiker赶上cyclist的时间,20minutes

作者: mandying    时间: 2009-12-18 06:21

 thanks so much~~ got it^.^





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