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

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## 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}

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