Question

A boat can go 48 km downstream and 16 km upstream in 6 hours. If the speed of the boat in still water is 10 km/hr, find the speed of the stream.​

Answer 1

48/(10+x) + 16/(10-x) = 6

x = 2km/h .

( solve karne ki jarurat na hai Bhai, saaf dikh Raha hai 48/12+16/8 = 6 hota hai )

Answer 2

The speed of the stream is 2 km/hr, 10/3 km/hr.

Step-by-step explanation:

Let the speed of stream is X km/hr

A boat can go 48 km downstream and 16 km upstream in 6 hours, that means the total time period is equal to

$\Rightarrow 6= \frac{48}{10+X}+ \frac{16}{10-X}$

$\Rightarrow 6= 16\times \left (  \frac{3}{10+X}+ \frac{1}{10-X}\right )$

$\Rightarrow 6= 16\times \left (  \frac{30-3X+10+X}{\left ( 10+X \right )\left ( 10-X \right )}\right )$

$\Rightarrow 300-3X^{2}= 8\times \left (  40-2X\right )$

$\Rightarrow 3X^{2}-16X+20= 0$

$\Rightarrow X=2, \frac{10}{3}$

The speed of the stream is 2 km/hr, 10/3 km/hr.