About 50,000 books are published each year, and about 130 million books exist around the world.
792 different groups of 5 books, in 95,040 different sequences.
There are many books available in market from different Authors and different Publishers.
6c4=15
The number of 4 different book combinations you can choose from 6 books is;6C4 =6!/[4!(6-4)!] =15 combinations of 4 different books.
Jerry Spinelli writes many different books with many different categories.
81
TEN
10!
You can wind up with 10 different pairs of books in your hand, which you can choose from a shelf of 5 books in 20 different ways.
Hindus Practice with many different books but some of the important ones are the four Vedas.
There are many different kinds self help books. There are books about religion, love, life and dealing with death. Most of the books are by renowned authors.
24 ways