2010 · Q27
The speed of a boat in still water is 11 km/h. It can go 12 km upstream and return downstream to the engine point in 2 hours 45 minutes. What is the speed of stream?
Elementary MathematicsTime and Distance
- A5 km/h
- B4 km/h
- C3 km/h
- D2 km/h
Explanation
12/(11-s)+12/(11+s)=11/4 gives s=5 km/h.