# A store has a sale on books. The price is $17.55 for one book, $16.70 each for 2 books, $15.85 each for 3 books, and $15 each for 4 books. If this pattern continues, how much per book will it cost to buy 7 books?

##### 2 Answers

Nov 9, 2016

#### Answer:

Cost for 7 books will be

#### Explanation:

The price per book forms an AP

The cost if 7 books are bought will be

Nov 9, 2016

#### Answer:

#### Explanation:

Price difference with each additional book purchased is

The formula for price per books seems to be:

where