Q1 · medium · AI-verified
A man rows 9 km/h in still water. The river is running at 3 km/h. If the man takes 3 hours to row to a place and come back, how far is the place?
- 12 km
- 15 km
- 18 km
- 9 km
Q2 · medium · AI-verified
A boat can travel 20 km downstream in 2 hours and 10 km upstream in 2.5 hours. What is the speed of the stream (in km/h)?
- 5 km/h
- 3 km/h
- 4 km/h
- 2 km/h
Q3 · easy · AI-verified
A train 150 m long passes a pole in 15 seconds. What is the speed of the train in m/s?
- 12 m/s
- 10 m/s
- 8 m/s
- 15 m/s
Q4 · medium · AI-verified
A train travels from city A to city B, a distance of 300 km, at a speed of 75 km/h. If it returns at 100 km/h, find the average speed for the entire journey.
- 85.71 km/h
- 87.5 km/h
- 83.33 km/h
- 90 km/h
Q5 · medium · AI-verified
Two trains 120 m and 180 m long are running towards each other at speeds of 42 km/h and 48 km/h. In how many seconds will they cross each other?
- 12 seconds
- 10 seconds
- 18 seconds
- 15 seconds