Answer:
144 pages
Step-by-step explanation:
Johan has read [tex]\frac{1}{4}[/tex] of the book that is 36 pages.
To find the total number of pages in the book, note that
[tex]\dfrac{1}{4}\ - \ 36\ \text{pages}\\ \\1\ - \ x\ \text{pages}[/tex]
Then
[tex]\dfrac{\frac{1}{4}}{1}=\dfrac{36}{x}\\ \\\dfrac{1}{4}x=36\\ \\x=4\cdot 36\\ \\x=144\ \text{pages}[/tex]