A national fast food company has just analyzed the effect of the latest sales promotion. It has determined that the sales decay for its milkshakes is given by S = 405, 000e 0.3%, where S is the weekly sales and a is the number of weeks that have passes since the end of the sales promotion. Round each answer to 2 decimal places. a) What will the sales 5 weeks after the end of the promotion? $ b) How many weeks after the end of the promotion will sales drop below 15,000, if no new campaign is started? weeks