Find the speed of a boat in still water if the boat goes 12 km/h along the stream and 4 km/h against the stream.
Answer & explanation
Correct answer: option 2
We know that,
Downstream speed = (x + y) km/h
Upstream speed = (x - y) km/h
Given,
Distance covered in downstream = 12 km/h
Distance covered in upstream = 4 km/h
Let the speed of the boat and stream be a km/h and b km/h respectively.
According to the above concept
= (a + b) = 12 km/h ....(1)
= (a - b) = 4 km/h ....(2)
Adding equations (1) and (2), we get
= 2a = 16
= a = 8 km/h