The speed of a boat when travelling downstream is 33 km/h, whereas when travelling upstream it is 27 km/h. What is the speed of the boat in still water?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 30 km/h.
Given that, downstream speed = 33 km/h
Upstream speed = 27 km/h
Let the speed of boat in still water and speed of current be x and y respectively.
According to the given question,
⇒ x + y = 33 ....(i)
And x - y = 27 .....(ii)
Adding the equations (i) and (ii),
⇒ 2x = 60
⇒ x = 30
Hence the speed of boat in still water is 30 km/h.