Ex 2. The following are exercises in present values: a. $100 at the end of three years is worth how much today, assuming a discount rate of (i) 100 percent? (ii) 10 percent? (iii) O percent?? b. What is the aggregate present value of $500 received at the end of each of the next three years, assuming a discount rate of (i) 4 percent? (ii) 25 percent? c. $100 is received at the end of one year, $500 at the end of two years, and $1,000 at the end of three years. What is the aggregate present value of these receipts, assuming a discount rate of (i) 4 percent? (ii) 25 percent?