a data from gmat forum

[diebeatsthegmat]

Car X leaves town A at 2 p.m. and drives towards town B at a constant rate of m miles/hr. 15 minutes later car Y begins driving from town B to town A at n miles/hr. If X and Y drive along same route, will car X be closer to town A or town B when it passes car Y.
1) Car X arrives in town B 90 mins after leaving A.
2) Car Y arrives in town A at same time as car X
logically i think its B but when i outlined to solve it, i think it should be C. how do you think? please explain

[shankar.ashwin]

IMO B

without any math, from statement B;

assuming both start at the same time, given they reach the destination at the same time, they would have met at midpoint of A and B.

But since Y starts from B 15 mins later(and obviously travels faster now) , car X would have crossed the mid point when they meet

[Anurag@Gurome]

Car X leaves town A at 2 p.m. and drives towards town B at a constant rate of m miles/hr. 15 minutes later car Y begins driving from town B to town A at n miles/hr. If X and Y drive along same route, will car X be closer to town A or town B when it passes car Y.
1) Car X arrives in town B 90 mins after leaving A.
2) Car Y arrives in town A at same time as car X
logically i think its B but when i outlined to solve it, i think it should be C. how do you think? please explain

(1) We don't have any information about the 2nd car; NOT sufficient.

(2) If they drive at constant speeds, then they pass each other only once, that is, they pass each other only when arriving to town B; clearly SUFFICIENT.

The correct answer is B.

[rahulvsd]

Hi,

How is statement 2 sufficient. I do understand that both cars will have same speeds, but can someone explain how statement 2 will be sufficient to solve this problem.

Thanks

[studentps2011]

Hi,

How is statement 2 sufficient. I do understand that both cars will have same speeds, but can someone explain how statement 2 will be sufficient to solve this problem.

Thanks

Statement 2:
Since car Y takes less time to travel the same distance, Y is faster than X. If they had crossed each other midway, Y would have reached destination faster than X. Since they are reaching their destinations at the same time, they should have crossed each other somewhere closer to B.

[GmatKiss]

IMO:C