On a tropical island there are 100 potential boat builders, numbered 1 through 100. each can build up to 16 boats a year, but anyone who goes into the boatbuilding business has to pay a fixed cost of $15. marginal costs differ from person to person. where y denotes the number of boats built per year, boat builder 1 has a total cost function c(y) = 15 + y. boat builder 2 has a total cost function c(y) = 15 + 2y, and more generally, for each i, from 1 to 100, boat builder i has a cost function c(y) = 15 +iy. if the price of boats is 40, how many boats will be built per year? a. 624 b. 200 c. 936 d. 400 e. any number between 640 and 656 is possible.

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