Let's start by using algebra to solve for the total number of pages in the book.
If Tim has read 40% of the book, then he has 60% of the book left to read (100% - 40% = 60%). We can express this as:
0.6x = 27
where x is the total number of pages in the book.
To solve for x, we can divide both sides of the equation by 0.6:
x = 27 ÷ 0.6
x = 45 ÷ 0.01
x = 4500
there are 4500 pages in the book.