CHAPTER 5 – 6
6. The time line is:
0 18
–
$73,00
0
$345,0
00
To answer this question, we can use either the FV or the PV formula. Both will give the same answer
since they are the inverse of each other. We will use the FV formula, that is:
Solving for r, we get:
r = (FV/PV)1/t – 1
7. To find the length of time for money to double, triple, etc., the present value and future value are
irrelevant as long as the future value is twice the present value for doubling, three times as large for
tripling, etc. To answer this question, we can use either the FV or the PV formula. Both will give the
same answer since they are the inverse of each other. We will use the FV formula, that is:
Solving for t, we get:
The length of time to double your money is:
0 ?
–$1 $2
FV = $2 = $1(1.061)t
The length of time to quadruple your money is:
0 ?
–$1 $4
Notice that the length of time to quadruple your money is twice as long as the time needed to double
your money (the slight difference in these answers is due to rounding). This is an important concept
of time value of money.