Oil leaked from a tank at rate of r(t) liters per hour.  The…

Oil leaked from a tank at rate of r(t) liters per hour.  The rate decreased as time passed and the values of the rate at two hour time intervals are shown in the table Use approximating rectangles based on left endpoints and calculate an estimate for the total amount of oil that leaked out in liters. Time (in hours) 0 2 4 6 8 r(t) (in liters per hour) 12 9 8 5 1