The sales, s, of a product have declined in recent years. there were 201 million sold in 1984 and 1.3 million sold in 1994. assume the sales are decreasing according to the exponential decay model, upper s left parenthesis t right parenthesis equals upper s 0 e superscript negative kt baseline . a) find the value k and write an exponential function that describes the number sold after time, t, in years since 1984. b) estimate the sales of the product in the year 2002. c) in what year (theoretically) will only 1 of the product be sold?

John and daphne are saving for their daughter ellen's college education. ellen just turned 10 at (t = 0), and she will be entering college 8 years from now (at t = 8). college tuition and expenses at state u. are currently $14,500 a year, but they are expected to increase at a rate of 3.5% a year. ellen should graduate in 4 years--if she takes longer or wants to go to graduate school, she will be on her own. tuition and other costs will be due at the beginning of each school year (at t = 8, 9, 10, and 11).so far, john and daphne have accumulated $15,000 in their college savings account (at t = 0). their long-run financial plan is to add an additional $5,000 in each of the next 4 years (at t = 1, 2, 3, and 4). then they plan to make 3 equal annual contributions in each of the following years, t = 5, 6, and 7. they expect their investment account to earn 9%. how large must the annual payments at t = 5, 6, and 7 be to cover ellen's anticipated college costs? a. $1,965.21b. $2,068.64c. $2,177.51d. $2,292.12e. $2,412.76