Peter read the same number of pages of his storybook each day. At the end of the
7th day, he was left with \( {1\over 4}\) of the total number of pages. After another 2 days, he
was left with 10 pages. How many pages are there in Peter's storybook?
Let the number of pages in his storybook ==P
Let the number of pages he read per day ==D
P - 7D ==1/4P
1/4P - 2D ==10, solve for P, D
P==280 pages in his book
D==30 pages per day he read
