Multiple choice

A person travels a certain distance at 3 km/hr and reaches 15 minutes late. If he travels at 4 km/hr, he reaches 15 minutes earlier. The distance he has to travel is

  1. 5 km

  2. 6 km

  3. 15 km

  4. 20 km
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let distance be d. Time at 3 km/hr = d/3. Time at 4 km/hr = d/4. Difference in time = 30 minutes = 0.5 hours. d/3 - d/4 = 0.5. d/12 = 0.5, so d = 6 km.

AI explanation

Using the standard formula for distance when two different speeds result in arriving early and late, Distance equals the product of the two speeds multiplied by the total time difference, all divided by the difference of the speeds. The speeds are 3 km/hr and 4 km/hr, and the total time difference between arriving 15 minutes early and 15 minutes late is 30 minutes, which is 0.5 hours. Applying the formula, Distance = (3 * 4 * 0.5) / (4 - 3). This calculates to 6 / 1, making the distance 6 km.

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