Liquid leaked from a damaged tank at a rate of r t liters per hour The rate decreased as time passed and values of the rate at five hour time intervals are shown in the table t hr r t L h 10 9 upper estimate F Find lower and upper estimates for the total amount of liquid that leaked out lower estimate liters 0 5 liters 10 15 20 25 9 9 9 1 8 3 7 5 6 9