To make some repairs to a school building, Edward's Construction Company mixes 16 tons of plaster. They only use 7 1/3 tons of it though. How much plaster do they have left? Write your answer as a fraction or as a whole or mixed number. tons

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! )