Question

How do find the new amount given 120 books increased by 55%?

Answer 1

Hint: To solve above question we will use the linear equation in one variable and percentage. Let us assume that x is the new amount of books. Then, we can write $x=120+120\times \dfrac{55}{100}$ , because 120 books are increased by 55% and also 55% is the shorthand representation of $\dfrac{55}{100}$.

Complete step by step answer:
We will use the concept of linear equation in one variable and percentage to solve the above question.
We can see from the question that 120 books are increased by 55% and we also know that 55% is the shorthand representation of $\dfrac{55}{100}$.
So, let us assume that x represents new amounts of books.
Since, we know that initially the number of books is 120 and it has increased by 55%.
So, increase in number of books = $\dfrac{55}{100}\times 120$ = $66$
Thus, total number of books after increment is given by ‘x’, so we can write x as:
x = 120 + increase in number of books
$\Rightarrow x=120+\dfrac{55}{100}\times 120$
$\therefore x=186$

Hence, new amounts of books are 186.

Note: We can also solve the above question by another method.
Since, we can say 120 is 100%.
So, when we increase the amount of books by 55% then, we have in total (100 + 55)% = 155% of books.
Thus, we will find 155% of 120 and we will use a unitary method to solve it.