单选题 A train travelling at a speed of 75 m.p.h. enters a tunnel 2(1/2)miles long. The length of the train is 1/4mile. How long does it take for all of the train to pass through the tunnel, from the moment the front enters to the moment the rear emerges?
【正确答案】 A
【答案解析】[解析] 火车的长度为0.25mile，隧道的长度为2.5miles，火车的速度为75mph，火车的长度+ 隧道的长度再除以火车的速度，就可以得出走完这个隧道所用的时间。