Question

A man rows to a place at a distance of 48 km and back in 14 hours. He finds that he can row 4 km with the stream in the same time as 3 km against the stream. What is the rate of the stream?

Answer 1

Ratio of the downstream speed to upstream speed = 4 : 3 

∴ Ratio of times taken to cover a certain distance downstream and upstream = 3 : 4 

Given 3\(x\) + 4\(x\) = 14 hrs ⇒ \(x\) = 2

∴ The man took 6 hours to row 48 km downstream and 8 hours to row 48 km upstream.

∴Speed downstream = \(\frac{48}6\) km/hr = 8 km/hr 

Speed upstream = \(\frac{48}8\) km/hr = 6 km/hr 

∴ Rate of stream = \(\frac12\)(8 - 6) km/hr = 1 km/hr.