What is the unit rate for 64 books on 4 shelves

Emily is entering a bicycle race for charity. her mother pledges $0.90 for every 0.75 mile she bikes. if emily bikes 18 miles, how much will her mother donate?

Hey hotel charges guests $19.75 a day to rent five video games at this rate which expression can be used to determine the charge for renting nine video games for one day at this hotel? pls

Sara made $253 for 11 hours of work. at the same rate how much would he make for 7 hours of work?