Daily crude oil production by Pemex, Mexico's national oil company, for 2008-2013 could be approximated by P(t) = 0.017t2 - 0.4t + 5.23 million barrels (8 ≤ t ≤ 13), where t is time in years since the start of 2000.† Find the derivative function dP/dt. dP/dt = At what rate was oil production changing at the start of 2011 (t = 11)?
Daily oil production was decreasing at a rate of ?? million barrels per year.