Explanation: Since it took Loin 5 hours to read 25% of the books and the entire book is 100%, 25% is 1/4 of the book. We add on 5 hours to every 1/4 of the book so 1/2=10 hours, 3/4= 15 hours and the entire book =20 hours. So the entire book would take 20 hours to read but the question is How many MORE hours so we subtract 5 hours from 20 hours which equals 15.
