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.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

我选了　Ｄ　，　理由如下，ａ　说了　在相遇前ｐ的速度，所以相遇点为　ｐ的速度乘２　．求出具体点．可得具体位置

ｂ　说Ｑ的全程速度，平均速度．那么相遇点位　Ｑ*２ 距离它的出发点的具体位置，　也可以求出具体位置，ｓｏ，　应该为Ｄ答案阿

前面ｎ多牛　说　为　Ａ　，为什么Ｂ不行啊？

请教数学高手．

题中说的parallel rail lines that are 250 miles long,是不是指两条线路每条250米长。还是说一共250米长。

如果是第一种说法的话，我觉得A应该是求不出来的。因为不知道另一个的速度。我是不太明白为什么选A。

条件2的意思是Q的全程平均速度是55，不是匀速行驶的意思，所以光凭条件2不能选出答案.