2016 · Q22
A man walking at 5 km/hour noticed that a 225 m long train coming in the opposite direction crossed him in 9 seconds. The speed of the train is
Elementary MathematicsTime, Speed and Distance
- A75 km/hour
- B80 km/hour
- C85 km/hour
- D90 km/hour
Explanation
The train covers 225 m in 9 s relative to the walker. This is a relative speed of 25 m/s, i.e. 90 km/h. They move in opposite directions, so the train's speed is 90−5 = 85 km/h, option C.