Katie has read 32%, so 32%=80 pages. To get the total number of pages, you have to divide 32 and 80 by 8 to get 4% and 10 pages. 4% of the book is 10 pages, and in order to get 100%, you have to multiply by 25(4*25=100) on both sides. Remember, what you do to one side, you do to the other side. That leaves you with 100% and 250 pages. The book is 250 pages long. If she has read 80 pages, you subtract 80 from 250 to find how many pages she has left to read. The difference is 170. Katie has 170 pages left to read.
