Question

A hiker covers $16km$ in $4$ hours . how long he go in $7$ hours.

Answer 1

Let a hiker covers distance $=x$

a hiker takes time $=y$

A hiker covers $16km$ in $=4hours$

A hiker covers $xkm$ in $=7hours$

As the distance increases, takes time also increases in the same ratio. It is a case of direct proportion.

We make use of the relation of type $\frac{x_1}{x_2}=\frac{y_1}{y_2}$

$x_1=16;x_2=x;y_1=4;y_2=7$

So,

$\frac{16}{x}=\frac{4}{7}$

$$\begin{gathered} 4\times x=16\times 7 \\ x=\frac{16\times 7}{4} \\ x=\frac{{\displaystyle \stackrel{4}{1\cancel{6}}}\times 7}{\cancel{4}} \\ x=4\times 7 \\ \therefore x=28 \end{gathered}$$

Hence the A hiker covers $7hours$ is $28km$