SAT Math: Non-CAS Practice

A bookstore sells a book for 13 dollars and sells 380 copies per week at that price. For every 1-dollar increase in price, 20 fewer copies are sold per week (and for every 1-dollar decrease, 20 more). Assume the relationship between price p (in dollars) and quantity q (in copies) is linear. What price p should the store charge to maximize its weekly revenue?
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