a cleaning service charges an hourly rate plus a flat fee of $15 for supplies. philip uses the service for 3.5 hours for his spring cleaning, and his total is $232. how can he correctly determine the hourly rate? divide the total cost,$232, by the number of hours,3.5. then, add the flat fee,$15, to the quotient. divide the total cost, 232 dollars by the number of hours, then, add the flat fee, 15 dollars to the quotient. add the supply fee,$15, to the total cost,$232. then, divide the sum by the number of hours,3.5. add the supply fee, 15 dollars to the total cost, then, divide the sum by the number of hours, subtract the supply fee,$15, from the total cost,$232. then, divide the difference by the number of hours,3.5.subtract the supply fee, 15 dollars from the total cost, then, divide the difference by the number of hours, divide the total cost, $232, by the number of hours, 3.5. then, subtract the flat fee, $15, from the quotient.