Terry read 1/5 of the number of pages in a book in the first hour, 3/8 of the remaining pages in the second hour. After that, he still had 45 more pages to read. How many pages are there in the book?
Let the number of pages ==P
P - 1/5P ==4/5P - pages left after 1st hour
4/5P - [4/5P * 3/8] ==1/2P - pages left after 2nd hour.
1/2P == 45
P ==45 x 2 ==90 - pages in the book.