Boats and Streams Questions in English

(A) Let the speed of the boat in still water be $x \, km/hr$ and the speed of the stream be $y \, km/hr$.
Speed downstream $= (x + y) \, km/hr$ and speed upstream $= (x - y) \, km/hr$.
Given that he rows $4 \, km$ downstream in the same time as $3 \, km$ upstream:
$\frac{4}{x + y} = \frac{3}{x - y} \Rightarrow 4x - 4y = 3x + 3y \Rightarrow x = 7y$.
Total time for the round trip of $48 \, km$ is $14 \, hours$:
$\frac{48}{x + y} + \frac{48}{x - y} = 14$.
Substitute $x = 7y$ into the equation:
$\frac{48}{7y + y} + \frac{48}{7y - y} = 14 \Rightarrow \frac{48}{8y} + \frac{48}{6y} = 14$.
$\frac{6}{y} + \frac{8}{y} = 14 \Rightarrow \frac{14}{y} = 14 \Rightarrow y = 1 \, km/hr$.
The rate of the stream is $1 \, km/hr$.