Mr. conway has three combines to harvest 1650 acres of corn. one combine has a 12-row header and the other two have a 16-row headers. the combine with the 12-row header harvests 11.4 acres per hour using 1.2 gallons of diesel fuel per acre. the combines with the 16-row headers harvest 16 acres per hour using 1.5 gallons of diesel fuel per acre a piece. the current fuel price is $2.00/gallon.
a. using all three combines, how many acres do they harvest in an hour?