There are m books in black cover and n books in blue cover, and all books are different. The number of ways these m + n books can be arranged on a shelf so that all the book in black cover are put side by side is

Step-by-step solution

Put all block cover books together A 1   A 12   A 3 … … A m → α Total number of books n + 1 These books be arranged in n + 1 ! ways and m books be arranged m ! ways No. of way = m ! ( n + 1 ) !