I've been given an economics problem in my calculus class. I have an example with a formula, from a previous assignment, but it doesn't seem to apply to my current problem.

Suppose that 1000 frankfurters can be sold every week at a food stand for $1 each. For every increase of $.20 per frankfurter, the number of frankfurters sold will decrease by 100. Write an equation which expresses the number of frankfurters sold as a function of price p in cents. What is the total revenue received from the sale of frankfurters per week if the price of each frankfurter is p?

I'm not sure how to even start on this equation. I do understand what the problem is asking.

Thank you for your help,

Anne Saunders