Sales and advertising a store finds that its sales decline after the end of an advertising campaign, with its daily sales for the period declining at the rate S'(t) = -1477.8e-0.2t, 0 ≤ t ≤ 35, where t is the number of days since the end of the campaign.
Suppose that S = 7389 units when t = 0.
(a) Find the function that describes the number of daily sales t days after the end of the campaign.
(b) Find the total number of sales 10 days after the end of the advertising campaign.