Trains A and B travel at the same constant rate in opposite

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Trains A and B travel at the same constant rate in opposite directions along the same route between Town G and Town H. If, after traveling for 2 hours, Train A passes Train B, how long does it take Train B to travel the entire distance between Town G and Town H?

(1) Train B started traveling between Town G and Town H 1 hour after Train A started traveling between Town H and Town G.

(2) Train B travels at the rate of 150 miles per hour.

The OA is the option A.

I don't know how to prove that the correct answer is the option A. Could anyone helps me here? Please.
Source: — Data Sufficiency |

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Trains A and B

by GMATGuruNY » Mon May 14, 2018 3:56 am

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VJesus12 wrote:Trains A and B travel at the same constant rate in opposite directions along the same route between Town G and Town H. If, after traveling for 2 hours, Train A passes Train B, how long does it take Train B to travel the entire distance between Town G and Town H?

(1) Train B started traveling between Town G and Town H 1 hour after Train A started traveling between Town H and Town G.

(2) Train B travels at the rate of 150 miles per hour.

The OA is the option A.
Statement 1:
Whereas A travels for 2 hours, B begins its journey 1 hour later and travels for 1 hour.
A ----------2 hours----------> meeting spot <-----1 hour----- B
Since A travels at r miles per hour for 2 hours to meet B, and B travels at r miles per hour for 1 hour to meet A, it takes a total of 3 hours to travel the entire distance at r miles per hour.
Thus, the time for B to travel the entire distance at r miles per hour = 3 hours.
SUFFICIENT.

Statement 2:
Since the distance between Town G and Town H can be ANY POSITIVE VALUE, the time for Train B to travel between the two towns cannot be determined.
INSUFFICIENT.

The correct answer is A.
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