Question

What is the value of $30\%$ of 400?

Answer 1

Hint: Now we want to find the value of $30\%$ of 400. Now we know that 30 percent is nothing but the ratio $\dfrac{30}{100}$ . Hence to find the value of the given expression we will multiply $\dfrac{30}{100}$ to 400 and hence simplify to find the value of the equation.

Complete step-by-step solution:
Now let us first understand the concept of percentage. Now the percentage is nothing but the ratios where the denominator is 100. Hence any ratio can be converted into percentage
Now to convert any ratio into percentage we will try to make the denominator as 100 without changing the value of the fraction.
For example consider the ratio $\dfrac{5}{25}$ . Now multiplying the numerator and denominator by 4 we get, $\dfrac{20}{100}$ . Hence the fraction represents 20 percent.
Now we want to calculate 30 percent of 400.
Now 30 percent is nothing but $\dfrac{30}{100}$ . Hence to find 30 percent of 400 we will multiply $\dfrac{30}{400}$ to 400.
Hence we have 30 percent of 400 is
\[\begin{align}
  & \Rightarrow \dfrac{30}{100}\times 400 \\
 & \Rightarrow \dfrac{3}{10}\times 400 \\
\end{align}\]
Now dividing 400 with 10 we get,
\[\begin{align}
  & \Rightarrow 3\times 40 \\
 & \Rightarrow 120 \\
\end{align}\] .
Hence 30 percent of 400 is 120.

Note: Now note that percentage is always written as ratio with denominator 100. Hence when multiplying the percentage always remember to divide the expression by 100. Also remember that we can also understand this as the ratio of $\dfrac{x}{400}$ must be $\dfrac{30}{100}$ hence we will find the value of x accordingly.