Trains Boats and Streams Practice Test 1 with solutions

Let the speed of the current = x m/min
Speed downstream = 48 + x
Speed upstream = 48 - x
According to the question,
$\frac{200}{8-\mathit{x}}-\frac{200}{48+\mathit{x}}$ = 10
$\frac{48+\mathit{x}-48+\mathit{x}}{2304-{\mathit{x}}^2}$ = $\frac{1}{20}$
40x = 2,304 - ${\mathit{x}}^2$
${\mathit{x}}^2$ + 40x - 32x - 2,304 = 0
(x + 72) (x - 32) = 0
x = 32 m/minutes
i.e., speed of the current = 32 m/minutes