Multiple choice

Bernardo drives to work at an average speed of $50$ miles per hour and returns along the same route at an average speed of $25$ miles per hour. If his total travel time is $3$ hours, what is the total number of miles in the round-trip?

  1. $225$
  2. $112.5$
  3. $100$
  4. $62.5$
  5. $50$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Average speed for a round trip is (2 * v1 * v2) / (v1 + v2) = (2 * 50 * 25) / 75 = 100/3 mph. Total distance = Average speed * Total time = (100/3) * 3 = 100 miles.

AI explanation

Using the total distance formula for equal distances, the average speed for the round trip is 2 x 50 x 25 / (50 + 25) = 2500 / 75 = 100/3 miles per hour. The total travel time is 3 hours, so applying the formula Distance = Speed x Time gives a total distance of 100/3 x 3 = 100 miles. The result is 100.

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