A motor boat runs at 22 km/hr downstream and at 14 km/hr upstream. What is the speed of the boat in still water?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 18 km/hr
Downstream speed \(=\) boat \(+\) stream and upstream speed \(=\) boat \(-\) stream. Adding the two speeds cancels the stream, leaving twice the boat’s speed.
Boat \(+\) stream \(=22\) and boat \(-\) stream \(=14\)
Adding: \(2\times\) boat \(=22+14=36\)
Speed of the boat in still water \(\displaystyle =\frac{36}{2}=18\) km/hr