The total sales of S (in thousands of DVD's) of a certain movie are given by the following formula where t is the number of months since the release of the DVD. Use the formula to answer the questions. 4012 S(t) = 2+150 a) Find S'(t). 12000t S'(t) = (12 + 150) 2 b) Find S(15) and S'(15). The value of S(15) rounded to the nearest hundredth is 24. The value of S'(15) rounded to the nearest hundredth is