Question

If you read 8 pages in a day, how many days will it take you to read 120 pages?

Answer 1

Hint: It is given that in one day someone reads 8 pages or 8 pages are read in 1 day so by unitary method we can find how many days it would take to read 1 page which is the division of 1 by 8. Now, we have got how many days it will take to read 1 page of the book and to find the number of days taken to read 120 pages. We are going to multiply 120 by the number of days to read 1 page. In this way, we can get how many days it will take to read 120 pages.

Complete step-by-step answer:
We have given that a person reads 8 pages of the book in 1 day. From this we can find the number of days in which a person reads 1 page of the book by dividing 1 by 8.
So, number of days in which a person can read 1 page of the book is equal to:
$\dfrac{1}{8}$
Now, we are asked to find the number of days in which a person reads 120 pages which we are going to find by multiplying 120 by the number of days a person took to read 1 page of the book. In the above , we have calculated that a person takes $\dfrac{1}{8}$ day to read 1 page of the book so multiplying 120 by $\dfrac{1}{8}$ we will get the number of days a person takes to read 120 pages.
$120\left( \dfrac{1}{8} \right)$
Numerator and denominator of the above expression is divisible by 4 so dividing 4 on numerator and denominator we get,
$\begin{align}
  & \dfrac{120}{4}\left( \dfrac{1}{\dfrac{8}{4}} \right) \\
 & =30\left( \dfrac{1}{2} \right) \\
\end{align}$
30 is divisible by 2 by 15 times so the above expression will look like:
15
Hence, it takes 15 days to read 120 pages.

Note: You can check whether the number of days that you have found to read 120 pages is correct or not by dividing 15 by 120 which will give you how many days to read 1 page of the book and then compare with the number of days that took to read 1 page that we have solved above.
Dividing 15 by 120 we get,
$\dfrac{15}{120}$
In the above fraction, numerator and denominator both is divisible by 15 so dividing numerator and denominator by 15 we get,
$\begin{align}
  & \dfrac{\dfrac{15}{15}}{\dfrac{120}{15}} \\
 & =\dfrac{1}{8} \\
\end{align}$
From the above calculations, we are getting that it takes $\dfrac{1}{8}$ days to read 1 page of the book which is the same as that we have got in the above solution. It means that we have correctly found the number of days to read 120 pages.