Mao Mao reads a book and reads 30 pages a day in 8 days. Therefore, the total number of pages in this book is 30 × 8 = 240 pages. If I read 40 pages a day, how many days can I finish it in advance? Using the ratio method to answer: To calculate the number of days you can read 40 pages a day compared to 30 pages a day, you can use the ratio method: Reading 40 pages a day was 40 - 30 = 10 pages more than reading 30 pages a day. Therefore, the number of days required to finish reading this book was 240 pages/10 pages/day = 240 days. Substituting this result into the original formula: 8 days/240 days = 0037125, which meant that reading 30 pages a day was about 37125 days earlier than reading 40 pages a day. Therefore, by reading 40 pages a day, he could advance by 0.037125 + 37125 = 47125 days. The answer was about four days in advance.