The average speed of a train running at a speed of 30 km/h during the first 100 km, at the speed of 40 km/h during the second 100 km and at the speed of 50 km/h during the last 100 km is nearly ________.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 38.3 km/h
According to the question,
Time taken to cover first 100 kilometres = 100/30 = 10/3
Time taken to cover second 100 kilometres = 100/40 = 10/4 =5/2
Time taken to cover third 100 kilometres = 100/50 = 2
Total Time Taken = 10/3 + 5/2 + 2 = (20 + 15 + 12)/6
Total Time = 47/6
Average speed = 300/(47/6) = 1800/47 = 38.29 ~ 38.30