请教一道OG的数据充分题，恳请各位NN帮忙解答。快要考试啦~

有一道Data sufficient的题

OG-93题

While driving on the expressway ,did Robin ever exceed the 55-mile-per -hour speed limit ?

(1)Robin drove 100 miles on the expressway.

(2)Robin drove for 2 hours on the expressway .

答案选的是E ,可我认为是C.OG 上的解释说：“Using the information from (1) and (2),the rate at which Robin traveled is equal to the    distance/time     or       100/2     ,for an average speed of 50 miles per hour . However ,because this is only Robin's average speed ,there is no way of knowing whether Robin at some point exceeded the speed limit and then ,at another point ,traveled under 50 mph.”

但是，即使我们不知道Robin具体是那个时间超过限速还是那个时间没有超速，平均速度已经算出是50了呀，这就已经说明他一定是超速了，也必定会有某些事件Robin是超过限速55的。为什么不选C呢？

恳请NN们指点一下

THANKS ~~~

大家帮忙解答~~~

谢谢了

很急用~~~~