Monthly sales of a particular personal computer are expected to decline at the following rate of S'(t) computers per month, where t is time in months and S(t) is the number of computers sold each month. S'(t)=-25t 2 3 The company plans to stop manufacturing this computer when monthly sales reach 500 computers. If monthly sales now (t=0) are 1,400 computers, find S(t). How long will the company continue to manufacture this computer?