Question

Twenty percent of what number is $18$ ?

Answer 1

Hint:In the given question, we are required to calculate a specific number whose twenty percent corresponds to the number provided to us in the problem, $18$. We must remember the formula for finding a specific percentage of a number as: $\text{Percentage} = \dfrac{\text{Part}}{\text{Whole}} \times 100\% $. The percentage of a number corresponds to the share or share in the whole thing.

Complete step by step answer:
So, we find the number whose $20\% $ corresponds to the number $18$ by using the formula for percentage as $\text{Percentage} = \dfrac{\text{Part}}{\text{Whole}} \times 100\% $ of the number x to be equal to $18$. So, the whole corresponds to the number x and the part corresponds to the number $18$ in this case. Also, the percentage is given to us as $20\% $. So, we substitute these known values in the above-mentioned formula. So, we get,
$ \Rightarrow 20\% = \dfrac{{18}}{x} \times 100\% $

Now, we have to find the value of x in the above equation. We use the method of transposition to shift the terms in the equation and find the value of a variable. Shifting the variable to the left side of the equation and constants to the right side of the equation, we get,
$ \Rightarrow x = \dfrac{{18}}{{20\% }} \times 100\% $
Simplifying the calculations, we get,
$ \Rightarrow x = \dfrac{{1800}}{{20}}$
Simplifying the calculations by canceling common factors in numerator and denominator, we get,
$ \Rightarrow x = 90$
So, the value of x is $90$.

Hence, twenty percent of the number $90$ is equal to $18$.

Note:Percentage is defined as the relative value that indicates the hundredth parts of any quantity or it can be defined as a number or ratio represented in the form of fractions of $100$ and is represented by the sign $\% $. The abbreviations used to represent the percentage are “pct” or ”pc”. The percentage formula $\text{Percentage} = \dfrac{\text{Part}}{\text{Whole}} \times 100\% $ can be used to find any parameter in the equation given the other parameters. If the partial number is greater than the whole quantity, the corresponding percentage will be greater than $100\% $ as $100\% $ is represented by the whole quantity.