Bob has some books. He puts 25 books each in 4 big boxes, and the other books in small boxes which can only hold 20 books each. He found the averagely, he put 22 books in one box. How many small boxes did he use?

Question

Bob has some books. He puts 25 books each in 4 big boxes, and the other books in small boxes which can only hold 20 books each. He found the averagely, he put 22 books in one box. How many small boxes did he use?

Answer 1

Let the number of books in the small boxes be x. So the total number of books in the small boxes is 20x.

The total number of books that Bob has is 25 books * 4 boxes = 100 books.

Therefore, 100 - 20x = x * 22

100 = 22x + 20x

100 = 42x

x = 100 / 42

x = 2.38

Since we can't have a fraction of a box, Bob used 3 small boxes to hold the remaining books.