Time Speed Distance — Prelims Questions

Two trains of lengths 150m and 200m are running in opposite directions at speeds of 60 km/h and 90 km/h respectively. In how much time will they completely cross each other?

A boat can travel 20 km downstream in 2 hours and the same distance upstream in 4 hours. What is the speed of the boat in still water?

Two cars start from the same point and travel in opposite directions at speeds of 80 km/h and 60 km/h. After how much time will they be 420 km apart?

A person travels first half of the distance at 40 km/h and the second half at 60 km/h. What is his average speed for the entire journey?

A train 240m long crosses a platform 160m long in 20 seconds. What is the speed of the train?