Find the present-value equivalent to the following geometrically increasing series of payments.

(PLEASE show work starting with formula used.)

a. A first-year base of $4,000 increasing at 4% per year to year 15 at an interest rate of 17% compounded continuously. Answer: $23,659

b. A first-year base of $100 increasing at 10% per year to year 12 at an interest rate of 6% compounded continuously.

c. A first-year base of $7,000 increasing at 7% per year to year 20 at an interest rate of 19% compounded continuously.