A company producing electric motors has established that, on the average, a new employee can assemble N(t) components per day after t days of on-the-job training, as shown in the table below (a new employee's productivity increases continuously with time on the job). Use left and right sums to estimate the area under the graph of N(t) from t=0 to t=60. Use three subintervals of equal length for each. Calculate an error bound for each estimate. t 0 N(t) 11 220 20 40 60 80 100 120 52 66 76 81 85 86 Using left sums, the area is (Simplify your answer.)