Peter and Tom shared the driving on a certain trip.

[Gmat_mission]

Peter and Tom shared the driving on a certain trip. If Peter and Tom both drove for the same amount of time, but Peter only drove 2/5 of the total distance, what was the ratio of Peter's average speed to Tom's average speed?

A. 1:5
B. 2:5
C. 1:2
D. 3:5
E. 2:3

[spoiler]OA=E[/spoiler]

Souce: GMAT Prep

[GMATGuruNY]

Peter and Tom shared the driving on a certain trip. If Peter and Tom both drove for the same amount of time, but Peter only drove 2/5 of the total distance, what was the ratio of Peter's average speed to Tom's average speed?

A. 1:5
B. 2:5
C. 1:2
D. 3:5
E. 2:3

Let the total distance = 5 miles and the time for each driver = 1 hour.
Since Peter drives 2/5 of the total distance -- 2 miles -- in 1 hour, Peter's speed = d/t = 2/1 = 2 miles per hour.
Since Tom drives the remaining distance -- 3 miles -- in 1 hour, Tom's speed = d/t = 3/1 = 3 miles per hour.
Resulting ratio:
(Peter's speed) : (Tom's speed) = 2:3.

The correct answer is E.

[Scott@TargetTestPrep]

Peter and Tom shared the driving on a certain trip. If Peter and Tom both drove for the same amount of time, but Peter only drove 2/5 of the total distance, what was the ratio of Peter's average speed to Tom's average speed?

A. 1:5
B. 2:5
C. 1:2
D. 3:5
E. 2:3

[spoiler]OA=E[/spoiler]

Souce: GMAT Prep

We can let the time driven by Peter and Tom = t. If we let the total distance = d, then Peter's distance = (2/5)d = 2d/5 and Tom's distance = (3/5)d = 3d/5.

Thus, Peter's rate is (2d/5)/t = 2d/(5t), and Tom's rate is (3d/5)/t = 3d/(5t).

The ratio of Peter's average speed to Tom's average speed is (2d/5t)/(3d/5t) = 10dt/(15dt) = 2/3.

Answer: E