Multiple choice

A long-distance bus service company operates a route between two cities that are 300 miles apart. On the way to the destination, the bus travels at an average speed of 75 miles per hour due to minimal traffic. However, on the return trip along the same route, heavy traffic reduces the average speed to 50 miles per hour. What is the average speed of the bus for the entire round trip?

  1. 55 miles per hour

  2. 57 miles per hour

  3. 60 miles per hour

  4. 62 miles per hour

  5. 66 miles per hour
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Average speed = Total distance / Total time. Total distance = 300 + 300 = 600 miles. Time 1 = 300/75 = 4 hours. Time 2 = 300/50 = 6 hours. Average speed = 600 / (4+6) = 60 mph.

AI explanation

For a round trip over the same distance, the average speed is found using the harmonic mean formula: 2xy / (x + y). Plugging in the speeds of 75 mph and 50 mph, we get (2 * 75 * 50) / (75 + 50) = 7500 / 125. Dividing this gives an average speed of 60 miles per hour for the entire journey.

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