One model of worldwide oil production is function provided by following formula, where P(t) is number of barrels, in billions, produced in year, t years after 1931. According to model, in what year did worldwide oil production get absolute maximum? Find what was that maximum? P(t) = 0.0000000218t^4 - 0.0000167t^3 - 0.00155t^2 - 0.002t + 0.22, 0 less than or equal to t less than or equal to 85 According to model, absolute maximum amount of oil produced worldwide was billion barrels in year.