The rate of depreciation (in dollars per year) for a certain truck is given by the function below, where t is in years and t-0 is the year of purchase. 5400(0.30.24t) f(t)- 2 1+0.3t+0.12t (a) find the total depreciation at the end of 4 years (b) how long will it take for the total depreciation to be at least $2700? (a) the total depreciation at the end of 4 years is approximately s (round to the nearest cent as needed.) (b) it will take approximately years for the total depreciation to be at least $270o round to two decimal places as needed.)