Chapter 04 – Future Value, Present Value, and Interest Rates
Chapter 4
Future Value, Present Value, and Interest Rates
Conceptual and Analytical Problems
1. Compute the future value of $100 at an 8 percent interest rate 5, 10, and 15 years into the
future. What would the future value be over these time horizons if the interest rate were 5
percent? (LO2)
Answer:
Future value in 5 years = $100*(1.08)5 = $146.93
Future value in 10 years = $100*(1.08)10 = $215.89
2. Compute the present value of a $100 investment made 6 months, 5 years, and 10 years from
now at 4 percent interest. (LO2)
Answer:
6 months: Present Value = 100/(1.04)0.5 = $98.06
Remember, you are calculating the present value of an investment to be made in the future.
3. Assuming that the current interest rate is 3 percent, compute the present value of a five-year,
5 percent coupon bond with a face value of $1,000. What happens when the interest rate goes
to 4 percent? What happens when the interest rate goes to 2 percent? (LO2)
Answer:
Present Value for 5-year 5 percent coupon bond with face value of $1000 (i=3%) =
Present Value for 5-year 5 percent coupon bond with face value of $1000 (i=4%) =
The present value falls when the interest rate rises to 4 percent.
Present Value for 5-year 5 percent coupon bond with face value of $1000 (i=2%) =
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Chapter 04 – Future Value, Present Value, and Interest Rates
The present value rises when the interest rate falls to 2 percent.
4. *Given a choice of two investments, would you choose one that pays a total return of 30
percent over five years or one that pays 0.5 percent per month for five years? (LO1)
Answer: To compare the investments, you need to measure their returns in the same units.
One option would be to convert both these returns to annual rates. The first investment gives
Alternatively, you could convert the first investment to a monthly return:
A third option would be to convert the monthly rate on the second investment into a 5-year
5. A financial institution offers you a one-year certificate of deposit with an interest rate of 5
percent. You expect the inflation rate to be 3 percent. What is the real return on your
deposit? (LO3)
6. Consider two scenarios. In the first, the nominal interest rate is 6 percent and the expected
rate of inflation is 4 percent. In the second, the nominal interest rate is 5 percent and the
expected rate of inflation is 2 percent. In which situation would you rather be a lender? In
which would you rather be a borrower? (LO3)
Answer: In the first scenario the real interest rate is 2 percent (the difference between the
nominal interest rate and the expected inflation rate) and in the second the real interest rate is
7. You decide you would like to retire at age 65, and expect to live until you are 85 (assume
there is no chance you will die younger or live longer). You figure that you can live nicely
on $50,000 per year. (LO3)
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Chapter 04 – Future Value, Present Value, and Interest Rates
a. Describe the calculation you need to make to determine how much you must save to
purchase an annuity paying $50,000 per year for the rest your life. Assume the
interest rate is 7 percent.
b. If you want to keep your purchasing power constant, how would your calculation
change if you expected inflation to average 2 percent for the rest of your life?
Answer:
b. If you want to have $50,000 in purchasing power for each year of your retirement,
you would need to calculate:
8. Most businesses replace their computers every two to three years. Assume that a computer
costs $2,000 and that it fully depreciates in 3 years, at which point it has no resale value and
is thrown away. (LO1)
a. If the interest rate for financing the equipment is equal to i, show how to compute the
minimum annual cash flow that a computer must generate to be worth the purchase.
Your answer will depend on i.
b. Suppose the computer did not fully depreciate but still had a $250 value at the time it
was replaced. Show how you would adjust the calculation given in your answer to
part (a).
c. What if financing can only be had at a 10 percent interest rate? Calculate the
minimum cash flow the computer must generate to be worth the purchase using your
answer to part (a).
Answer:
a. If x = minimum annual cash flow:
9. Some friends of yours have just had a child. Thinking ahead, and realizing the power of
compound interest, they are considering investing for their child’s college education, which
will begin in 18 years. Assume that the cost of a college education today is $125,000. Also
assume there is no inflation and no tax on interest income used to pay college tuition and
expenses. (LO2)
a. If the interest rate is 5 percent, how much money will your friends need to put into
their savings account today to have $125,000 in 18 years?
b. What if the interest rate were 10 percent?
c. The chance that the price of a college education will be the same 18 years from now
as it is today seems remote. Assuming that the price will rise 3 percent per year, and
that today’s interest rate is 8 percent, what will your friend’s investment need to be?
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Chapter 04 – Future Value, Present Value, and Interest Rates
d. Return to part (a), the case with a 5 percent interest rate and no inflation. Assume that
your friends don’t have enough financial resources to make the entire investment at
the beginning. Instead, they think they will be able to split their investment into two
equal parts, one invested immediately and the second invested in five years. Describe
how you would compute the required size of the two equal investments, made five
years apart.
Answer:
a. PV = $125,000/(1.05)18 = $51,940.08
c. If the price rises 3 percent per year, the cost of a college education in 18 years will be:
d. If x is the size of each investment:
10. You are considering buying a new house, and have found that a $100,000, 30-year fixed-rate
mortgage is available with an interest rate of 7 percent. This mortgage requires 360 monthly
payments of approximately $651 each. If the interest rate rises to 8 percent, what will
happen to your monthly payment? Compare the percentage change in the monthly payment
with the percentage change in the interest rate. (LO1)
Answer: If the annual interest rate is 8 percent, then the monthly rate is (1.08)1/12 – 1 =
0.006434
Using the equation from Appendix 4A:
11. *Use the Fisher equation to explain in detail what a borrower is compensating a lender for
when he pays her a nominal rate of interest. (LO3)
Answer: The Fisher equation illustrates that the nominal interest rate (i) can be broken down
into two components where i = r + пe. Taking i to be an annual interest rate, the borrower is
12. If the current interest rate increases, what would you expect to happen to bond prices?
Explain. (LO2)
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Chapter 04 – Future Value, Present Value, and Interest Rates
Answer: Interest rates and bond prices are inversely related so bond prices will fall when
13. Which would be most affected in the event of an interest rate increase– the price of a
five-year coupon bond that paid coupons only in years 3, 4, and 5 or the price of a five-year
coupon bond that paid coupons only in years 1, 2, and 3, everything else being equal?
Explain. (LO2)
Answer: The price of the bond with the later payments will fall by relatively more. The
payments are made further into the future, so the change in the interest rate has a greater
14. Under what circumstances might you be willing to pay more than $1,000 for a coupon bond
that matures in three years, has a coupon rate of 10 percent, and a face value of $1,000?
(LO2)
Answer: If the interest rate in the market were less than 10 percent, the present value of the
payment flows associated with the bond would be higher than $1000. You can use the
15. *Approximately how long would it take for an investment of $100 to reach $800 if you
earned 5 percent? What if the interest rate were 10 percent? How long would it take an
investment of $200 to reach $800 at an interest rate of 5 percent? Why is there a difference
between doubling the interest rate and doubling the initial investment? (LO1)
Answer: Using the rule of 72, we know that if the interest rate is 5 percent, it will take
(You can check that your calculations are approximately correct using the future value
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Chapter 04 – Future Value, Present Value, and Interest Rates
16. Rather than spending $100 today on paint today, you decide to save the money until next
year, at which point you will use it to paint your room. If a can of paint costs $10 today, how
many cans will you be able to buy next year if the nominal interest rate is 21 percent and the
expected inflation rate is 10 percent? (LO3)
Answer: Saving $100 today means forgoing 10 cans of paint. Since the funds grow in
nominal terms by 21 percent, $121 will be available in one year. Expected inflation is 10
percent, so the anticipation is that can of paint in one year will cost $11. Thus, the number of
17. Recently, some lucky person won the lottery. The lottery winnings were reported to be $85.5
million. In reality, the winner got a choice of $2.85 million per year for 30 years or $46
million today. (LO2)
a. Explain briefly why winning $2.85 million per year for 30 years is not equivalent to
winning $85.5 million.
b. The evening news interviewed a group of people the day after the winner was
announced. When asked, most of them responded that, if they were the lucky winner,
they would take the $46 million up-front payment. Suppose (just for a moment) that
you were that lucky winner. How would you decide between the annual installments
or the up-front payment?
Answer:
a. $2.85 million per year is not equivalent to winning $85.5 million because of the time
b. I would calculate which payment option gave me the highest present value. I would
look at the market to determine the appropriate interest rate to use and calculate the
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