You must give up your full-time job, which paid $50,000 per year, and you worked part-time for half of the year.
The average retail price of the cookbooks will be $30, and their average cost will be $20.
Assume that the equation for demand is Q = 40,000 - 500P, where
Q = the number of cookbooks sold per month
P = the retail price of books.
Show what the demand curve would look like if you sold the books between $25 and $35.