Question: Projected retirement funds based on data from the central provident fund of a certain country (a government agency similar to the social security administration), the estimated cash in the fund in 2003 is given by
A(t) = -96.6t4 + 403.6t3 + 660.9t2 + 250 (0 ≤ t ≤ 5)
Where a(t) is measured in billions of dollars and t is measured in decades, with t = 0 corresponding to 2003. Find the interval where a is increasing and the interval where a is decreasing and interpret your results.