Question

What is the number, if 30 percent of the number is 120?

Answer 1

Hint: We will use a percentage formula for solving this question. To discover $30\% $ of a number, we take it to be a variable x, and then we find $30\% $ of x and equal it to 120 as per the provided, and then we solve for the value of x.

Complete step by step answer:
We will assume the required number is x.
We have given 30 percent of the number is 120.
So, according to the relation
$ \Rightarrow 30\% \times x = 120$
$ \Rightarrow \dfrac{{30}}{{100}} \times x = 120$
We will multiply both side by 100,
$ \Rightarrow 30x = 120 \times 100$
We have divided whole equation by 30,
$ \Rightarrow x = \dfrac{{120 \times 100}}{{30}}$
$ \Rightarrow x = 400$
Hence, the $30\% $ of the 400 is 120.

Note:
The key to solving these sorts of problems is to apply the percentage calculation to an unknown and then equating it to the provided number. If we need to convert a percentage to a decimal, divide it by 100, according to the percentage formula. Students should not get confused between words in percentage problems. In these problems generally “of” stands for multiplication and “is” stands for equal.