How are you guys doing today ? Need help with this ASAP

Question and answers are in the attached picture. you so much in advance.

Can someone me with this problem i don't understand i need

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! )