A rowing boat moves at 5 m/s downstream and at 3 m/s upstream. What is the speed of the boat in still water, in km/hr?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 14.4 km/hr
The speed in still water is half the sum of the downstream and upstream speeds. To change m/s to km/hr, multiply by \(\frac{18}{5}\).
Speed in still water \(\displaystyle =\frac{5+3}{2}=4\) m/s
\(\displaystyle 4\times\frac{18}{5}=\frac{72}{5}=14.4\) km/hr