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by f2001290 » Wed Jun 13, 2007 1:41 am
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.

I went with A, but the OA isn't.
Source: — Data Sufficiency |

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by mschling52 » Thu Jun 14, 2007 9:09 am
I agree with you on A. We know that train P would have traveled 140 miles, so train Q must have traveled 110. So, we know that P is closer to its destination.

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by drhomler » Thu Jun 14, 2007 9:50 am
Totally agree with A. If they were both traveling for 2 hrs and one train is averaging 70m/hr it will have traveled 140 miles the total distance is 250 therefore the other train will have traveled 110 and you can answer the question which one was closer. Statement 2 doesnt tell us anything but the speed of one train for the whole trip so we dont know anything about when they passed each other so you cant get relative distance

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by recocollins » Tue Jun 19, 2007 2:09 pm
I say C because Statement 1 tells us nothing about the speed of train Q and Statement 2 tells us nothing about the speed of train P.

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by mschling52 » Wed Jun 20, 2007 6:21 am
Statement 1 actually does tell us the speed of train Q. Since P has traveled 140 miles and the 2 trains are passing one another, Q must have traveled 110 miles in the 2 hours = 55 miles per hour.

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by jrbrown2 » Wed Jun 20, 2007 7:33 pm
I'd say A

Statement 1 is sufficient so that leaves answer choices A or D.
Statement 2 says that the average speed of train Q was 55mph for the entire trip. This doesn't tell you how much distance was covered when the two trains met, so we dont know which train was closer to their destination.

IMO i don't see how statement 2 could possibly answer the ques. (or maybe my brain is just fried from too much studying)