A train 325 m long passes a person walking at 4 km/h in the same direction in 13 seconds. What is the speed of the train?

💡 Solution & Explanation

When both move the same way, the train passes the person at the difference of their speeds. That relative speed = 325 m ÷ 13 s = 25 m/s = 25 × 18/5 = 90 km/h. So the train's own speed = 90 + 4 = 94 km/h. Forgetting to add the walking speed gives 90 km/h.