Question

Uppose you have 6 different math books and 5 different english books.

a.in how many different ways, 4 math books and 3 english books can be arranged on a bookshelf?clearly describe how you arrived at your answer.

Answer 1

a) 4 different math books and 3 different English books can be arranged in

`(4+3)!=7!=5040` ways. This is because all the books are different.

But if you choose 4 math books from 6 different math books and 3 English books from 5 different English books, the number ways of arranging on the shelf is

`C(6,4)*C(5,3)*(4+3)!=(6!)/(4!2!) (5!)/(3!2!) 7!=756,000`