Question

Ed planned to read 25 pages a day of his favorite book by some deadline. However, he read 8 pages more a day and there were just 10 pages left reading 2 days before the deadline. How many pages the book has?

Answer 1

175 pages

Explanation:

Let's call 'd' the number of days before the deadline, and 'n' the total number of pages of the book.

We have the following equations:

(1)
`25 d = n` --> if we multiply the number of pages per day (25) times the number of days (d), we get the total number of pages of the book (n)

(2)
`(25+8)(d-2)=n-10` --> he reads 8 pages more per day (so, 25+8), for a number of days equal to (d-2) (d is the deadline), and he reads a total of n-10 pages (because only 10 are left)

We can substitute (1) into (2) and we find:

`33(d-2)=25d-10\\33d-66=25d-10\\33d-25d=66-10\\8d=56\\d=7`

So, the deadline is 7 days, and from eq.(1) we find the number of pages in the book:

`n=25d=25 (7)=175`