How to solve this Data Sufficiency question?

Question

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

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

Mohit C · Accepted Answer

This is a classic distance = rate &times; time question. You&rsquo;re told both trains travel toward each other and meet after 2 hours. The goal is to figure out which train was closer to its destination at that point.
Statement 1 says Train P travelled at 70 mph. So in 2 hours, it went 140 miles. Since the track is 250 miles long, Train P still had 110 miles to go. That means Train Q had travelled only 110 miles, so it still had 140 miles left. Train P was closer to its destination at the meeting point. So this is sufficient.
Statement 2 gives Train Q&rsquo;s average speed for the whole trip but says nothing about Train P&rsquo;s speed. Without knowing how far Train Q had travelled in the 2 hours, we can&rsquo;t say which train was nearer to its destination. This statement alone is not sufficient. Final answer is  A, only statement 1 is sufficient.

Divakshi Arora · Answer

The total distance between stations is 250 miles. The trains passed each other after traveling for 2 hours.

Statement 1 says Train P's speed was 70 mph. So it traveled 140 miles in 2 hours, leaving 110 miles to go. That means Train Q had gone 110 miles and still had 140 left. Train P was closer. Sufficient.
Statement 2 gives Train Q&rsquo;s average speed as 55 mph, but nothing about Train P&rsquo;s speed. We can&rsquo;t compare who was closer. Not sufficient.
Without knowing both speeds, we can&rsquo;t compare distances.

Only Statement 1 is sufficient. Answer is A.