Difficulty Level: Hard
Stats: 1,431 / 4,351 ( 32.89% ) got this right
A motorboat, whose speed in 15 km/hr in still water goes 30 km downstream and comes back in a total of 4 hours 30 minutes. The speed of the stream (in km/hr) is:
- 2 km/hr
- 3.25 km/hr
- 4 km/hr
- 4.5 km/hr
- 5 km/hr