Question

A pump empties $500l$of water in$5minutes$. How long will it take to empty a tank containing $1200l$ of water? How much water can this pump empty in$7minutes?$

Answer 1

Given that

A pump empties $500l$of water in$5minutes$

Let it will take $xminutes$ to empty a tank containing $1200l$ of water

we have

$$\begin{gathered} 500:5=1200:x \\ 500x=5\times 1200 \\ x=\frac{6000}{500} \\ x=12 \end{gathered}$$

Hence, it will take $12minutes$ to empty a tank containing $1200l$ of water.

Let $yl$ water can this pump empty in$7minutes.$

then,

$$\begin{gathered} 500:5=y:7 \\ 500\times 7=5\times y \\ y=\frac{3500}{5} \\ y=700 \end{gathered}$$

Hence in $7minutes$ it will empty $700l$ water.