Question

A boat running upstream takes 8 horus and 48 min. to cover a certain distance, while it take 4 hours to cover same distance running downstream. What is the ratio between the speed the boat and speed of water current respectively?

Answer 1

$$\begin{gathered} \mathrm{Let}\mathrm{the}\mathrm{speed}\mathrm{of}\mathrm{boat}\mathrm{be}\mathrm{x}. \\ \mathrm{And}\mathrm{speed}\mathrm{of}\mathrm{water}\mathrm{be}\mathrm{y}. \\ \mathrm{So}, \\ \mathrm{Distance}\mathrm{covered}\mathrm{upstream}\mathrm{in}8\mathrm{hours}48\min =\mathrm{distance}\mathrm{covered}\mathrm{downstream}\mathrm{in}4\mathrm{hours}. \\ \left(\mathrm{x}-\mathrm{y}\right)8\frac{4}{5}=\left(\mathrm{x}+\mathrm{y}\right)4 \\ \frac{44}{5}\mathrm{x}-\frac{44}{5}\mathrm{y}=4\mathrm{x}+4\mathrm{y} \\ \frac{44\mathrm{x}-20\mathrm{x}}{5}=\frac{20\mathrm{y}+44\mathrm{y}}{5} \\ 24\mathrm{x}=64\mathrm{y} \\ \frac{\mathrm{x}}{\mathrm{y}}=\frac{64}{24} \\ \mathrm{x}:\mathrm{y}=8:3\mathrm{ANS}... \end{gathered}$$