GMAT Math Practice - Speed Time Races

Concept: Speed Distance Time relation. Basics of mixtures and weighted average.

This GMAT Math practice question is a rates question. Concept: Finding time travelled at a particular speed. Covers basics of mixtures and weighted average.

Question: Jane covered a distance of 340 miles between city A and city taking a total of 5 hours. If part of the distance was covered at 60 miles per hour speed and the balance at 80 miles per hour speed, how many hours did she travel at 60 miles per hour?

  1. 2 hours 30 minutes
  2. 3 hours
  3. 2 hours
  4. 1 hour 45 minutes
  5. None of these

Explanatory Answer

Video explanation will be added soon

Let Jane travel 'x' at 60 miles per hour.
As the total time taken to cover 340 miles is 5 hours, Jane would have traveled (5 - x) hours at 80 miles per hour.

Distance covered at 60 miles per hour = Speed * time = 60 * x = 60x miles.
Distance covered at 80 miles per hour = Speed * time = 80 (5 - x) = 400 - 80x miles.

Total distance covered = Distance covered at 60 miles per hour + Distance covered at 80 miles per hour.
Therefore, total distance = 60x + 400 - 80x.
Total distance travelled = 340 miles.
Therefore, 340 = 60x + 400 - 80x
20x = 60 or x = 3 hours.

Choice B is the correct answer.

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