(2) Answer the following questions (20 points, 2 points each)

(a) How many years will it take for an investment to double at an interest rate of 4%?

(b) The operating cost for a water purification facility is expected to average $8,500/year for the next five years. What is the present worth of the operating costs at an interest rate of 7%?

(c) An environmental engineering consultant expects to construct a $5 million nature-based resilience facility (cost estimate as of today) 4 years from now. They have funds available that can be invested at 9% compounded annually. How much should they invest to have $10 million at the end of 4 years?

(d) A company borrows $6,000 in December 2012 at an interest rate of 7%. (a) What uniform annual payment should the company make, starting Dec 2013, to repay the entire amount by Dec 2022? (b) If the company chooses to make a single payment in December 2022 to repay the entire principal, how much would they have to pay in Dec 2022?