A story book has 235 pages. After reading it for ten days, Ling Ling still has 75 pages left.

After ten days, Lingling was left with 75 pages, so the average number of pages she read every day was: 75 pages/10 days = 75 pages/day As there were still 75 pages left, Lingling still needed to read them every day on average: 23 - 75 = -525 Because the number of pages was negative, Ling Ling had read the book many times after ten days, but she hadn't finished it.