GMAT Quant Practice | GMAT Rates Q6

This GMAT quant practice question is from rates - speed, distance, and time. The concept tested is to compute the average speed of travel. An easy, GMAT 550 level, quantitative reasoning sample question.

Question 6: Steve traveled the first 2 hours of his journey at 40 mph and the remaining 3 hours of his journey at 80 mph. What is his average speed for the entire journey?

1. 60 mph
2. 56.67 mph
3. 53.33 mph
4. 64 mph
5. 66.67 mph

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Video Explanation

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Explanatory Answer | GMAT Average Speed

Step 1: Compute Total Distance Travelled

Average speed of travel = \\frac{\text{Total distance travelled}}{\text{Total time taken}})
Total distance traveled by Steve = Distance covered in the first 2 hours + distance covered in the next 3 hours.
Distance covered in the first 2 hours = speed × time = 40 × 2 = 80 miles.
Distance covered in the next 3 hours = speed × time = 80 × 3 = 240 miles.
Therefore, total distance covered = 80 + 240 = 320 miles.

Step 2: Compute Average Speed

Total time taken = 2 + 3 = 5 hours.
Total distance travelled = 320 miles.
Hence, average speed = \\frac{\text{Total distance travelled}}{\text{Total time taken}} = \frac{320}{5}) = 64 miles per hour.

Choice D is the correct answer.