Question 449998
Ricardo has 6 books written by five different authors.in how many ways can he arrange them on a shelf so that the two books by the same author are next to each other?
-----------------
ways to arrange the 2 books = 2
---
Now treat those 2 books as one "book".
---
ways to arrange the 4 books = 4! = 24
---
Total # of ways to arrange the 5 books: 2*24 = 48
====================================================
Cheers,
Stan H.