A boat covers 64 km upstream in 8 hours and 120 km downstream in 12 hours. What is the speed (in m/s) of the boat in still water?
Answer & explanation
Correct answer: option 1
The speed of the boat in still water is = (Speed of the boat in downstream + Speed of the boat in upstream) $\div$ 2
The boat covers 64 km upstream in 8 hours
So, Speed of the boat in upstream = 8 km/h
Also, the boat covers 120 km downstream in 12 hours
Speed of the boat in downstream = 10 km/h
The speed of the boat in still water = (10 + 8) $\div$ 2 = 9 km/h
or
9 $\times$ \(\frac{5}{18}\) = 2.5 m/s