Question

$ 18 $ is what percent of $ 72? $

Answer 1

Hint: Percentage is defined as the fraction where the denominator is always hundred. Percentage is always with the reference to the hundred. Here we are given the whole and the part of the whole and have to find its percentage.

Complete step-by-step answer:
First of all we will frame the mathematical expression with the given data.
 $
  72 = 100\% \\
  18 = x\% \;
  $
Perform cross-multiplication, where the left hand side of one equation is multiplied with the term in the right hand side of the other equation.
 $ x(72) = 18 \times 100 $
Make the required term “x” the subject, when the term multiplicative on one side is moved to the opposite side then it goes to the denominator.
 $ x = \dfrac{{18 \times 100}}{{72}} $
Find the factors of the term on the numerator and the denominator –
 $ x = \dfrac{{18 \times 25 \times 4}}{{18 \times 4}} $
Common factors from the numerator and the denominator cancel each other and therefore remove $ 25 $ and $ 4 $ from the numerator and the denominator.
 $ x = 25\% $
Hence, $ 18 $ is $ 25\% $ of $ 72 $
So, the correct answer is “ $ 25\% $ ”.

Note: Do not get confused between the terms fraction and the percentage. Fractions are expressed as the part of the whole and is represented as the numerator upon the denominator. While simplifying the fraction, it always tries to convert the denominator in tens, hundreds and directly shift the decimal point depending on the number of zeros in the denominator.