Mathematically, the future value of an investment if compounded annually at a rate of i for n years will be where n = the number of years during which the compounding occurs i = the annu
Trang 1
CHAPTER 5 The Time Value of Money
CHAPTER ORIENTATION
In this chapter the concept of a time value of money is introduced, that is, a dollar today isworth more than a dollar received a year from now Thus if we are to logically compareprojects and financial strategies, we must either move all dollar flows back to the present orout to some common future date
CHAPTER OUTLINE
I Compound interest results when the interest paid on the investment during the first
period is added to the principal and during the second period the interest is earned onthe original principal plus the interest earned during the first period
A Mathematically, the future value of an investment if compounded annually at
a rate of i for n years will be
where n = the number of years during which the compounding
occurs
i = the annual interest (or discount) rate
PV = the present value or original amount invested at the
beginning of the first periodFVn = the future value of the investment at the end of n
years
1 The future value of an investment can be increased by either
increasing the number of years we let it compound or bycompounding it at a higher rate
2 If the compounded period is less than one year, the future value of an
investment can be determined as follows:
where m= the number of times compounding occurs during the
year
Trang 2II Determining the present value, that is, the value in today's dollars of a sum of money
to be received in the future, involves nothing other than inverse compounding Thedifferences in these techniques come about merely from the investor's point of view
A Mathematically, the present value of a sum of money to be received in the
future can be determined with the following equation:
where: n = the number of years until payment will be
received,
i = the interest rate or discount rate
PV = the present value of the future sum of moneyFVn = the future value of the investment at the end of n
years
1 The present value of a future sum of money is inversely related to
both the number of years until the payment will be received and theinterest rate
III An annuity is a series of equal dollar payments for a specified number of years
Because annuities occur frequently in finance, for example, bond interest payments,
we treat them specially
A A compound annuity involves depositing or investing an equal sum of money
at the end of each year for a certain number of years and allowing it to grow
1 This can be done by using our compounding equation, and
compounding each one of the individual deposits to the future or byusing the following compound annuity equation:
t
i)(1
where: PMT = the annuity value deposited at the end of each
year
i = the annual interest (or discount) rate
n = the number of years for which the annuity will
lastFVn = the future value of the annuity at the end of the
nth year
B Pension funds, insurance obligations, and interest received from bonds all
involve annuities To compare these financial instruments we would like toknow the present value of each of these annuities
1 This can be done by using our present value equation and discounting
each one of the individual cash flows back to the present or by usingthe following present value of an annuity equation:
1
Trang 3where: PMT = the annuity deposited or withdrawn at the end
of each year
i = the annual interest or discount rate
PV = the present value of the future annuity
n = the number of years for which the annuity will
last
C This procedure of solving for PMT, the annuity value when i, n, and PV are
known, is also the procedure used to determine what payments are associatedwith paying off a loan in equal installments Loans paid off in this way, inperiodic payments, are called amortized loans Here again we know three ofthe four values in the annuity equation and are solving for a value of PMT,the annual annuity
IV Annuities due are really just ordinary annuities where all the annuity payments have
been shifted forward by one year Compounding them and determining their presentvalue is actually quite simple Because an annuity, due merely shifts the paymentsfrom the end of the year to the beginning of the year, we now compound the cashflows for one additional year Therefore, the compound sum of an annuity due is
FVn(annuity due) = PMT (FVIFAi,n) (1 + i)
A Likewise, with the present value of an annuity due, we simply receive each
cash flow one year earlier – that is, we receive it at the beginning of eachyear rather than at the end of each year Thus the present value of an annuitydue is
PV(annuity due) = PMT (PVIFAi,n) (1 + i)
V A perpetuity is an annuity that continues forever, that is every year from now on this
investment pays the same dollar amount
A An example of a perpetuity is preferred stock which yields a constant dollar
dividend infinitely
B The following equation can be used to determine the present value of a
perpetuity:
where: PV = the present value of the perpetuity
pp = the constant dollar amount provided by the perpetuity
i = the annual interest or discount rate
VI To aid in the calculations of present and future values, tables are provided at the
back of Financial Management (FM)
A To aid in determining the value of FVn in the compounding formula
FVn = PV (1 + i)n = PV (FVIFi,n)tables have been compiled for values of FVIFi,n or (i + 1)n in Appendix B,
"Compound Sum of $1," in FM
Trang 4B To aid in the computation of present values
tables have been compiled for values of
or PVIFi,nand appear in Appendix C in the back of FM
C Because of the time-consuming nature of compounding an annuity,
t
t
i)(1
t
t
i)(1
or FVIFAi,nfor various combinations of n and i
D To simplify the process of determining the present value of an annuity
V Spreadsheets and the Time Value of Money
A While there are several competing spreadsheets, the most popular one is
Microsoft Excel Just as with the keystroke calculations on a financial calculator, a spreadsheet can make easy work of most common financial calculations Listed below are some of the most common functions used with Excel when moving money through time:
Calculation: Formula:
Present Value = PV(rate, number of periods, payment, future value, type)Future Value = FV(rate, number of periods, payment, present value, type)Payment = PMT(rate, number of periods, present value, future value,
type)Number of Periods = NPER(rate, payment, present value, future value, type)Interest Rate = RATE(number of periods, payment, present value, future
value, type, guess)
Trang 5where: rate = i, the interest rate or discount rate
number of periods = n, the number of years or periodspayment = PMT, the annuity payment deposited or received at the
end of each periodfuture value = FV, the future value of the investment at the end of n
periods or yearspresent value = PV, the present value of the future sum of moneytype = when the payment is made, (0 if omitted)
0 = at end of period
1 = at beginning of periodguess = a starting point when calculating the interest rate, if
omitted, the calculations begin with a value of 0.1 or 10%
ANSWERS TO END-OF-CHAPTER QUESTIONS
5-1 The concept of time value of money is recognition that a dollar received today is
worth more than a dollar received a year from now or at any future date It existsbecause there are investment opportunities on money, that is, we can place our dollarreceived today in a savings account and one year from now have more than a dollar.5-2 Compounding and discounting are inverse processes of each other In compounding,
money is moved forward in time, while in discounting money is moved back in time.This can be shown mathematically in the
compounding equation:
FVn = PV (1 + i)n
We can derive the discounting equation by multiplying each side of
this equation by and we get:
5-3 We know that
FVn = PV(1 + i)nThus, an increase in i will increase FVn and a decrease innwill
decrease FVn
5-4 Bank C which compounds daily pays the highest interest This occurs because,
while all banks pay the same interest, 5 percent, bank C compounds the 5 percentdaily Daily compounding allows interest to be earned more frequently than theother compounding periods
5-5 The values in the present value of an annuity table (Table 5-8) are actually derived
from the values in the present value table (Table 5-4) This can be seen, by
Trang 6examining the values represented in each table The present value table gives values
for various values of i and n Thus the value in the present value of annuity table for
an n-year annuity for any discount rate i is merely the sum of the first n values in thepresent value table PVIFA 10%,10yrs = 6.145
5-6 An annuity is a series of equal dollar payments for a specified number of years
Examples of annuities include mortgage payments, interest payments on bonds,fixed lease payments, and any fixed contractual payment A perpetuity is an annuitythat continues forever, that is, every year from now on this investment pays the samedollar amount The difference between an annuity and a perpetuity is that aperpetuity has no termination date whereas an annuity does
SOLUTIONS TO END-OF-CHAPTER PROBLEMS
Solutions to Problem Set A
5-1A (a) FVn = PV (1 + i)n
Trang 7Thus n = 15 years (because the value of 2.079 occurs in the 15
year row of the 5 percent column of Appendix B)
Thus, i = 12% (because the Appendix B value of 3.896 occurs in
the 12 year row in the 12 percent column)
Trang 9t
t
0.05) (1
n
0
t
i) (1
5
0
t
0.1) (1
n
0
t
i) (1
7
0
t
0.07) (1
n
0
t
i) (1
1 3
0
t
Trang 10t (1 i)
1
1
t (1 0.03)
1
compounded for 1 year
Trang 11(c) There is a positive relationship between both the interest rate used to
compound a present sum and the number of years for which the
Trang 12compounding continues and the future value of that sum.
Trang 13(e) An increase in the stated interest rate will increase the future value of a given
sum Likewise, an increase in the length of the holding period will increasethe future value of a given sum
PV = $8,500 (6.492)
Since the cost of this annuity is $50,000 and its present value is $55,182,given an 11 percent opportunity cost, this annuity has value and should beaccepted
Trang 141
PV = $7,000 (8.442)
Since the cost of this annuity is $60,000 and its present value is only
$59,094, given an 11 percent opportunity cost, this annuity should not beaccepted
PV = $8,000 (7.963)
Since the cost of this annuity is $70,000 and its present value is only
$63,704, given an 11 percent opportunity cost, this annuity should not beaccepted
5-11A Year 1:FVn = PV (1 + i)n
FV1 = 15,000(1 + 0.2)1
FV1 = 15,000(1.200)
FV1 = 18,000 booksYear 2:FVn = PV (1 + i)n
FV2 = 15,000(1 + 0.2)2
FV2 = 15,000(1.440)
FV2 = 21,600 booksYear 3: FVn = PV (1 + i)n
FV3 = 15,000(1.20)3
FV3 = 15,000(1.728)
FV3 = 25,920 books
Trang 15Book sales 25,000 20,000 15,000
years
The sales trend graph is not linear because this is a compound growth trend Just as compound interest occurs when interest paid on the investment during the first period
is added to the principal of the second period, interest is earned on the new sum Book sales growth was
compounded; thus, the first year the growth was 20 percent
of 15,000 books for a total of 18,000 books, the second year
20 percent of 18,000 books for a total of 21,600, and the third year 20 percent of 21,600 books for a total of 25,920
Trang 16n
0
t
i) (1
15
0
t
0.06) (1
Thus, PMT = $644.44
$1,079.50 = $500 (FVIF i%, 10 yr.)
10
0
t
.10) (1
n
0
t
i) (1
10
0
t
.09) (1
$10,000,000 = PMT(15.193)
Trang 17Thus, PMT = $658,197.855-18A One dollar at 12.0% compounded monthly for one year
= $1(1.127)
= $1.127One dollar at 13.0% compounded annually for one year
Trang 18= $10,000 + $50,000 + $10,000
Trang 19PV = FVn (PVIFi,n)
PV = $2,000(PVIF10%, year 1) + $3,000(PVIF10%, year 2) +
$4,000(PVIF10%, year 3) - $5,000(PVIF10%, year 4) +
$5,000(PVIF10%, year 5)
= $2,000(.909) + $3,000(.826) + $4,000(.751) - $5,000(.683) + $5,000(.621)
= $1,818 + $2,478 + $3,004 - $3,415 + $3,105
= $6,990
Investment B:
PV = $2,000(PVIF10%, year 1) + $2,000(PVIF10%, year 2) +
$2,000(PVIF10%, year 3) + $2,000(PVIF10%, year 4) +
$5,000(PVIF10%, year 5)
= $2,000(.909) + $2,000(.826) + $2,000(.751) + $2,000(.683) + $5,000(.621)
= $1,818 + $1,652 + $1,502 + $1,366 + $3,105
= $9,443
Trang 20Investment C:
PV = $5,000(PVIF10%, year 1) + $5,000(PVIF10%, year 2) -
$5,000(PVIF10%, year 3) - $5,000(PVIF10%, year 4) +
1
t t 15
1
1 .06)
(1
1
1
1
$30,000 = $10,000 (PVIFAi%, 5 yr.)
Trang 21(1 1
= $25,000 (.074)
= $1,850Thus take the $10,000 in 12 years
n
0
t
i) (1
5
0
t
.12) (1
Trang 22n
0
t
i) (1
15
0
t
.07) (1
n
0
t
i) (1
$30,330 = PMT (FVIFA7%, 15 yr.)
5-33A (a) This problem can be subdivided into (1) the compound value of the $100,000
in the savings account (2) the compound value of the $300,000 in stocks, (3)the additional savings due to depositing $10,000 per year in the savingsaccount for 10 years, and (4) the additional savings due to depositing
$10,000 per year in the savings account at the end of years 6-10 (Note the
$20,000 deposited in years 6-10 is covered in parts (3) and (4).)(1) Future value of $100,000
FV10 = $100,000 (1 + 07)10
(2) Future value of $300,000
Trang 23n 0
10 0
t
.07)(1
= $10,000 (13.816)
= $138,160(4) Compound annuity of $10,000 (years 6 - 10)
5
0
t
.07) (1
t (1 10)
1
Trang 255-40A FVn = PV (FVIFi%, n yr.)
$6,500 = 12(FVIFi%, 37 yr.)solving using a financial calculator:
= $50,000 (8.365-3.170) + $250,000 (.149) + $50,000 (0.112 + 102) + $100,000 (.092)
= $259,750 + $37,250 + $10,700 + $9,200
= $316,900(b) If you live longer than expected you could end up with no money later on in
life
Trang 265-42A rate (i) = 8%
number of periods (n) = 7payment (PMT) = $0present value (PV) = $900type (0 = at end of period) = 0
Future value = $1,542.44Excel formula: =FV(rate,number of periods,payment,present value,type)
Notice that present value ($900) took on a negative value
5-43A In 20 years you’d like to have $250,000 to buy a home, but you only have $30,000
At what rate must your $30,000 be compounded annually for it to grow to $250,000 in
20 years?
number of periods (n) = 20payment (PMT) = $0present value (PV) = $30,000future value (FV) = $250,000type (0 = at end of period) = 0
guess =
i = 11.18%
Excel formula: =RATE(number of periods,payment,present value,future
value,type,guess)
Notice that present value ($30,000) took on a negative value
5-44A To buy a new house you take out a 25 year mortgage for $300,000 What will your
monthly interest rate payments be if the interest rate on your mortgage is 8 percent?
Two things to keep in mind when you're working this problem: first, you'll have toconvert the annual rate of 8 percent into a monthly rate by dividing it by 12, andsecond, you'll have to convert the number of periods into months by multiplying 25times 12 for a total of 300 months
Excel formula: =PMT(rate,number of periods,present value,future value,type)
type (0 = at end of period) = 0
monthly mortgage payment = ($2,315.45)
Notice that monthly payments take on a negative value because you pay them