Mr. Reader has six different Spiderman comic books, five different Archie comic books and four different Garfield comic books. When stacked, all of the Spiderman comic books are grouped together, all of the Archie comic books are grouped together and all of the Garfield comic books are grouped together. In how many different orders can these 15 comic books be stacked in a pile with the covers facing up and all of them facing the same direction? Express your answer as a whole number.

Answer 1

the three kinds of comics can be arranged in 3! ways
Among each group of n comics of the same type, there are n! ways to arrange them.

So, there are 3!6!5!4! ways to arrange the 15 comics.