Hint: Here the number is unknown to us. So, assume that the number is $x$ . Then apply the condition and form an equation.
Complete step-by-step answer:
Here we have to find out a number whose 25% is 500. The number is unknown to us. So we have to assign a variable for the number.
Let us assume that the number is $x$ .
Now we have to find out the value of $x$ using the given condition.
It is given in the question that 25% of the number is 500.
Now, percent means “out of 100”. Or we can say percent means divided by 100. For example, instead of saying “it rained 14 days out of every 100 days”, we can say “it rained 14% of the time”.
So, 25% means 25 out of 100.
Thant means:
$25%=\dfrac{25}{100}$
Now, we have 25% of a number is 500. That means:
$\Rightarrow x\times \dfrac{25}{100}=500$
$\Rightarrow \dfrac{25x}{100}=500$
Now, multiply both sides of the equation by 100.
$\Rightarrow \dfrac{25x}{100}\times 100=500\times 100$
$\Rightarrow 25x=500\times 100$
Divide the both sides of the equation by 25.
$\Rightarrow \dfrac{25x}{25}=\dfrac{500\times 100}{25}$
$\Rightarrow x=\dfrac{500\times 100}{25}$
$\Rightarrow x=500\times 4=2000$
Hence the value of $x$ is 2000.
Therefore 25% of 2000 is 500. That means 2000 is our required answer.
Note: From the question always try to understand what we need to find out or what is unknown in that question. Then assign a variable.
If p% of x is y then the relation between them is:
$\begin{align}
& \Rightarrow \dfrac{p}{100}\times x=y \\
& \Rightarrow \dfrac{px}{100}=y \\
\end{align}$
If we know any two of them we can find out the third one. Here in this problem:
$p=25,y=500$, $x$ is unknown.
$\Rightarrow \dfrac{25x}{100}=500\Rightarrow x=2000$
