Its 550 pages, because if you know that he reads 55 pages an hour, then you can multiply the number of pages her reads in an hour by 4 hours. That's 220. Then he will still need 330, just add them together and you will get 550.
How Long Did It Take Naoya to read the entire book?
10 hours.
You know it takes him 4 hours to read 220, and you also know there's 550 pages. And you also know, he can only read 55 pages an hour, so just divide 550 ÷ 55.
