Give the step-by-step reasoning process and then the final answer. Xander read 20% of his 500-page book in one hour. The next night he read another 20% of the book. On the third night, he read 30% of his book. How many pages does he have left to read?
The first night he read 20% of his 500 - page book so he read .20 * 500 = 100 pages. The book is 500 pages and he read 100 so that leaves 500 - 100 = 400 pages. The second night he reads 20% of the 500 pages so he read .20 * 500 = 100 pages. The book is now 400 pages and he read 100 so that leaves 400 - 100 = 300 pages. The third night he read 30% of the book so he read .30 * 500 = 150 pages. The book is now 300 pages and he read 150 pages so he has 300 - 150 = 150 pages left to read.
The final answer: 150.