The speed of a motor boat in still water is 15 km/hr. It takes 3 hours to go 33 km upstream. What is its speed when it goes downstream?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 19 km/hr
The upstream run gives the speed of the stream; adding it to the boat’s speed gives the downstream speed.
Upstream speed \(\displaystyle =\frac{33}{3}=11\) km/hr
Speed of the stream \(=15-11=4\) km/hr
Downstream speed \(=15+4=19\) km/hr