A 150-meter-long train crosses another 100-meter-long train moving in the opposite direction in 12 seconds. If the speed of the first train is 60 km/h, estimate the speed of the second train.
Show answer & explanation
Correct answer: B
Explanation
Length of the first train = 150 meters
Length of the second train = 100 meters
Total distance = 150 + 100 = 250 meters
Time = 12 seconds
Relative speed = 250 ÷ 12 = 20.83 m/s
= 20.83 × 18/5 = 75 km/h
First train + Second train = 75
60 + Second train = 75
Second train = 15 km/h