智力测试题 英语I only have two minutes to catch a train,but there are two miles from my house to the train station.If I go the first mile at therate of45 miles per hour,at what rate must I go the second mile in order to catch the train?
问题描述：
智力测试题 英语
I only have two minutes to catch a train,but there are two miles from my house to the train station.If I go the first mile at therate of45 miles per hour,at what rate must I go the second mile in order to catch the train?
答
前面所用时间为4/3
所以后一半用时2/3
可见用时为前一半的2/1
两段都为1英里
所以后一半用的时间应为前一半的2倍
既45*2=90m/h
答
2分钟（1/30小时）-1/45小时=1/90小时
1/90小时要走剩下的1 mile，所以1小时走90 mile
即90 miles per hour
答
45 miles per hour 就是0.75mile每分钟,所以第一英里,他用了1分20秒
剩下40秒,要走一英里,速度就是每分钟1.5英里,也就是90miles per hour
答案90 Miles/h