Question

What % of Rs. 120 is 15?

Answer 1

Hint: To solve the question we have the simple idea about percentage. At first we have to assume that x% of Rs. 120 is 15. Then we have to find out x% of 120 and equate the result to 15 which will give an equation. Then by solving the equation we will get the value of x which is the required answer.

Complete step-by-step answer:
We know that a percentage is a number or ratio that represents a fraction of 100. For example 20% represents\[\dfrac{20}{100}\].
Consider that x% of Rs. 120 is 15. According to the definition of percentage, x% represents the fraction\[\dfrac{x}{100}\] that is if we have say total data of ‘n’ items, and if we take sample of ‘m’ items form total data of ‘n’ items, then sample over total data dives the ratio of amount of sample from total data and when ratio is multiplied by 100, then the expression we get is percentage of sample ‘m’ in total data ‘n’
 Now x% of 120 means \[\dfrac{x}{100}\]of 120, which is given by\[\dfrac{x}{100}\times 120=\dfrac{6x}{5}\].
But according to the question,
\[\dfrac{6x}{5}=15\] ………………………………. (1)
Now multiplying both the sides of eq. (1) by\[\dfrac{5}{6}\], we will get,
\[\begin{align}
  & \Rightarrow \dfrac{5}{6}\times \dfrac{6x}{5}=\dfrac{5}{6}\times 15 \\
 & \Rightarrow x=12.5 \\
\end{align}\]
Therefore 12.5% of Rs. 120 is 15

Note: Percentage has no unit of measurement, but when we calculate percentage always put a sign of % after the final numerical answer. Always remember that we put measure of sample over total data not total data over sample data as this will change the value of ratio, hence percentage will also get changed. Try not to make any calculation mistakes.