A boat takes 3.0 hours to travel 30 km down a river, then 5.0 hours to return. How fast is the river flowing

Einstein office equipment has a rental plan for office machines. a fax machine that lists for $722.98 can be rented for 22% of the price annually. the state imposes a usage charge of 3.2%. if stephen hawking travel decides to rent the fax machine, what will its total monthly rental charge be?