# Ex.8.3 Q3 Compairing Quantities - NCERT Maths Class 7

## Question

The population of a city decreased from \(25,000\) to \(24,500.\) Find the percentage decrease.

## Text Solution

**What is Known?**

The change in the population of a city (from \(25,000\) to \(24,500\))

**What is Unknown?**

The percentage decrease

**Reasoning:**

The decrease in population can be calculated by subtracting earlier (initial) population from present (final) population and percentage decrease in population can be obtained using the formula

Percentage decrease

\[\begin{align}=\frac{{{\text{Change}}\;{\text{in}}\;\;{\text{quantity}}}}{{{\text{Initial}}\;{\text{quantity}}\;}}{\rm{ \times 100}}\end{align}\]

**Steps:**

Decrase in city population

\[\begin{align}&= 25000 - 24500\\&= 500\end{align}\]

Percentage decrease

\[\begin{align}&= \,\frac{{{\text{Change}}\;{\text{in}}\;\;{\text{population}}}}{{{\text{Initial}}\;{\text{population}}\;}}{\rm{ \times 100}}\\&= \,\frac{{{\text{500}}}}{{{\text{25000}}}}{\rm{ \times 100}}\\&= \,{\text{2% }}\end{align}\]