ricardo has 6 books written by 5 different authors, in how many ways can he arrange them on a shelf so that the 2 books by the same author are next to eachother?

Question

anonymous · Answer

5! There are 5 ways to have the two books next to each other.  Each case has 4! permutations of the other books.  5*4!=5!=120

anonymous · Answer

wait i made a mistake

anonymous · Answer

multiply that by 2 to permute the two books next to each other.  2*5!=240.  sorry

anonymous · Answer

6*1*4*3*2*1=144

anonymous · Answer

? kbetz how did you come up with that