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 ```I need help with the following problem relating to Present Values- Compute the present value of a \$100 cash flow for the following combinations of discount rates and times: A. r=8% t=10 years B. r =8% t=20 yrs C. r=4% t=10 yrs D. r=4% t=20 yrs```
 ```Dear Fan, Here is a QUICK Answer: Let's assume that we are talking about calendar years and we are sitting there on January 1st asking this question. The answer depends on whether the \$100 payments are received on January 1, meaning today, or whether the money is received on December 31st. The payment received on January 1 of each year is a "beginning annuity." The payment received on December 31 of each year is an "ending annuity." Most calculators assume that you are calculating for an ending annuity. ENDING ANNUITIES: A. 8% 10 \$671.01 B. 8% 20 \$981.81 C. 4% 10 \$811.09 D. 4% 20 \$1,359.03 BEGINNING ANNUITIES: A. 8% 10 \$724.69 B. 8% 20 \$1,060.36 C. 4% 10 \$843.53 D. 4% 20 \$1,413.39 Here is a website from Duke University that explains some of the math: http://www.duke.edu/~charvey/Classes/ba350_1997/preassignment/preassign.htm Frankly, I just plugged the variables (time, rate, and payment) into my trusty Hewlett-Packard 12C calculator. Good enough? If you need help making the formulas work from the Duke site, please let me know by clicking the CLARIFICATION button. Thanks, weisstho-ga```