A man rows to a place 48 km distant and come 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. The rate of the stream is:

Explanation:-

$$\eqalign{ & {\text{Suppose}}\,{\text{he}}\,{\text{move}}\,4\,km\,{\text{downstream}}\,{\text{in}}\,x\,hours. \cr & {\text{Then}}, \cr & {\text{Speed}}\,{\text{downstream}} = \left( {\frac{4}{x}} \right)km/hr \cr & {\text{Speed}}\,{\text{upstream}} = \left( {\frac{3}{x}} \right)km/hr \cr & \therefore \frac{{48}}{{\left( {4/x} \right)}} + \frac{{48}}{{\left( {3/x} \right)}} = 14\,or\,x = \frac{1}{2} \cr & {\text{So,}}\,{\text{Speed}}\,{\text{downstream}} = 8km/hr, \cr & {\text{Speed}}\,{\text{upstream}} = 6km/hr. \cr & {\text{Rate}}\,{\text{of}}\,{\text{the}}\,{\text{stream}} \cr & = \frac{1}{2}\left( {8 - 6} \right)km/hr = 1\,km/hr \cr}$$