2. Two people read the same book. A read 9 pages on the first day, then read 3 pages more than the day before, and read only 30 pages on the last day. B I read 15 pages on the first day, then I read 3 pages more than the day before, and I only need to read 12 pages on the last day. How many pages are there in this book? "
3. The ratio of the original number of basketball between school A and school B is 2: 1. If school A gives four basketballs to school B, the basketball quantity ratio between school A and school B is 4:3. How many basketballs are there in a school?