17.) which of the following investments is larger? a.)$15,000 is deposited annually for 10 years and earns 4% interest compounded annually. b.) $500 is deposited monthly for 20 years and earns 4% interest compounded monthly. 18.) Using either logarithms or a graphing calculator, find the time required for the initial amount to be at least equal to the amount. $8000 deposited at 4% compounded quarterly, to reach at least $12,400 19.) Find the interest rate for each deposit and compound amount. $6000 accumulating to $7965.19, compounded quarterly for 6 years. 20.) Find the indicated term of the geometric requence. a = 4, r = 3; Find the 4th term. 21.) See attachment below.