Hi I'm having some trouble with this question:

The selling price of a mathematics textbook is related to the number of pages in the text. A 300 page book sells for $25 and each additional 10 pages increases the price by $1.
- What is the linear equation relating the selling price to the number of pages?
- Predict the cost of a 264 page book?
THANK YOU :)

Selling Price = 0.1n - 5