binomial distribution

Question

A member of a book club wishes to purchase two books from a selection of eight books recommended for a certain month. In how many ways can she choose them?

Answer 1

Let's think of this from a logical standpoint. We have two options. When you make the second selection, you will have one less. We will multiply these together.

8 X 7 = 56

Now, we will divide this by how many times the order does matter. In our example, if the arrange of books A and B are the same as B and A, these are the same way . Therefore, we say that there's two ways in which order doesn't matter. So we will divide 56 by 2 to get 28. There are 28 different ways to pick out 2 books.