Respuesta :

its not really a formula but
Dayo has 1/5th of the pages left to read
1/5th of 500 is 100 (500/5)
Dayo has not read 100 pages
A book has 500 pages and 4/5 th of pages were read.

500 * [tex]\frac{4}{5}[/tex] = 400

And what are the remaining pages of the book?

500 - 400 = 100

So, there are 100 pages left to read.