A staff from Exponent Books is arranging 1 cookbook, 2 children’s books, 3 classics and 4 self-help books on a shelf. In how many ways can the books be arranged if

Question

a. the books can be placed anywhere

b. all books on the same subject matter have to be together except for the classics books which may be placed anywhere.

Answer 1

(a) 10!

(b) 2+4 = 6 of the positions have been selected.

(10 pick 4) = 10! / (10-4)! = 10! / 6! = 10*9*8*7 = 5040