GMAT Math Practice - Speed Time Races

Concept: Average speed

This GMAT quant practice question is a rates - speed, distance, and time question covering the concept of computing average speed of travel.

Question: Jim travels the first 3 hours of his journey at 60 mph speed and the remaining 5 hours at 24 mph speed. What is the average speed of Jim's travel in mph?

  1. 42 mph
  2. 36 mph
  3. 37.5 mph
  4. 42.5 mph
  5. 48 mph

Explanatory Answer

Video explanation will be added soon

Compute total distance travelled and total time taken

Average speed = \\frac{\text{Total distance}}{\text{Total Time}}\\)

Total distance traveled by Jim = Distance covered in the first 3 hours + Distance covered in the next 5 hours.

Distance covered in the first 3 hours = 3 * 60 = 180 miles.

Distance covered in the next 5 hours = 5 * 24 = 120 miles.

Therefore, total distance traveled = 180 + 120 = 300 miles.

Total time taken = 3 + 5 = 8 hours.

Compute average speed

Average speed = \\frac{\text{Total distance}}{\text{Total Time}} = \frac{300}{8}\\) = 37.5 mph.

Choice C is the correct answer.

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