Question

After reading 7/9 of a book,40 pages are left .How many pages are there in the book

Answer 1

$\large{\sf{\underline{\text{Answer}}}}$:-

Let total pages of book = ${x}$

Pages which were read = $\dfrac{7x}{9}$

$\underline{\text{According To Question :-}}$

$\implies$ $\dfrac{7x}{9}$ = ${x}$ - 40

$\implies$ $\dfrac{7x}{9}$ - ${x}$ = -40

$\implies$ $\dfrac{7x - 9x}{9}$ = -40

$\implies$ $\dfrac{-2x}{9}$ = -40

$\implies$ $\dfrac{2x}{9}$ = 40

$\implies$ 2 ${x}$= 40 × 9

$\implies$ 2 ${x}$ = 360

$\implies$ ${x}$ = $\dfrac{360}{2}$

$\implies$ ${x}$ = 180

Total pages of book is 180.

$\underline{\text{So, there are 180 pages in the book.}}$

Answer 2

$\textsf{\textbf{\large{Given :-}}}$
• After reading 7/9 of a book,40 pages are left

$\textsf{\textbf{\large{To\:Find :-}}}$

• Total number of pages in the book.

$\textsf{\textbf{\large{Solution :-}}}$

First of all,
Let us assume that the total number of pages in the book be $\textsf{\textbf{\large{x}}}$

So,

7/9 of x = 7/9 × x

Now According to question,

x - 7/9x = 40
9x/9 - 7x/9 = 40
2x/9 = 40
2x = 40 × 9
2x = 360
x = 360/2
x = 180

$\textsf{\textbf{\large{Hence,}}}$ Total number of pages in the book were $\textsf{\textbf{\large{180}}}$