Hi LUANDATO,

David's explanation about the relationship between Rate and Time is spot-on. If you don't realize how that relationship applies in these types of questions, then you can still answer this question with some basic arithmetic.

We're told that Airplane A traveled a 360-mile route in 2 hours. Thus, it traveled at 360/2 = 180 miles per hour.

We're also told that Airplane B traveled the SAME distance at an average speed that was 1/3 SLOWER than the average speed of airplane A. One third of 180 is 60, so Airplane B traveled at 180 - 60 = 120 miles per hour.

We're asked for the number of hours that it took Airplane B to travel the route....
Distance = (Rate)(Time)
360 miles = (120 mi/hour)(T)
360/120 = T
3 hours = T

Final Answer: E

GMAT assassins aren't born, they're made,
Rich

BTGmoderatorLU wrote:Airplanes A and B traveled the same 360-mile route. If airplane A took 2 hours and airplane B traveled at an average speed that was 1/3 slower than the average speed of airplane A, how many hours did it take airplane B to travel the route?

(A) 2

(B) 2(1/3)

(C) 2(1/2)

(D) 2(2/3)

(E) 3

The OA is E.

I don't understand why that is the correct answer. Please can any expert explain this PS question for me? Thanks.

We find that airplane A traveled at an average speed of 360/2 = 180 mph.

Since airplane B traveled at an average speed that was 180 * (1/3) = 60 mph less than that of airplane A, the speed of airplane B is 180 - 60 = 120 mph.

Thus, it took airplane B 360/120 = 3 hours to travel the route.

Answer: E