Multiple choice

A train travels first 300 km at an average speed of 30 km/hr and further travels the same distance at an average speed of 60 km/hr. Average speed over the total distance is

  1. 35 km/hr

  2. 40 km/hr

  3. 45 km/hr

  4. 42 km/hr
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Average speed = Total Distance / Total Time. Total distance = 300 + 300 = 600 km. Time 1 = 300/30 = 10 hrs. Time 2 = 300/60 = 5 hrs. Average speed = 600 / 15 = 40 km/hr.

AI explanation

Since equal distances are traveled at two different speeds, we use the harmonic mean formula for average speed: 2xy / (x + y). Substituting the given speeds gives (2 * 30 * 60) / (30 + 60) = 3600 / 90 = 40 km/hr. The average speed over the total distance is 40 km/hr.

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