The ratio of the number of books obtained by Class Two and Class Three is 5 to 7.

1 class and class 2 get 2 to 3 books.

How many books are there in each class?

Answer: 1 class 90.

Category 2, 135 books

Class 3, 189

The process of solving problems

2x 5 = 10 3x 5 = 15 3x 7 = 2 1 10+ 15+2 1 = 46

4 14x 46 10 = 904 15 = 135 4 14x 46 2 1 = 189。