I'm at a bookstore with $\$35$ in my pocket and a $20\%$-off coupon. What is the cost of the most expensive book I can buy with my money and

19. I'm at a bookstore with 35$ in my pocket and a 20%-off coupon. What is the cost of the most expensive book I can buy with my money and the coupon? (Assume that there are books of every possible price in the bookstore. It's a large bookstore!)