Radio Shack TRS-80 Model 100 Basic Manual page 49

140 B = (1 -
(1 +
I)~(M-N» / I
150
B
=
MP
*
B
180
PRINT "PRINCIPAL REMAINING IS
$"; B
Here is an example of the execution of this program:
INTEREST RATE (0 -100)7 12.S
AMOUNT OF LOAN
?
71200
NUMBER OF YEARS7 30
MONTHLY PAYMENT IS
$
759.88752679191
TOTAL AMOUNT PAID IS
$
273559.50964509
CURRENT YEAR OF LOAN? 10
PRINCIPAL REMAINING 18 S 66883.232623196
This example would be typical of an
$
89,000 home purchased with a conventional
80% mortgage at 12.5% over 30 years. The amount of the loan would be
$
71,200.
The discouraging result of running this example is that the total you will have to pay
over the 30 years is $ 273,559.51. By entering a current year of 10, you can see that
the principal remaining unpaid after 10 years is still
$
66,883.23. This means that in
10 years you have paid
$71,200 - $66,883.23
=
$4,316.77
toward the original amount borrowed.
What you have learned:
In this lesson, the use of string and numeric variables has been illustrated. Arithmetic
expressions have been used in the calculation of interest and mortgage rates. The
INPUT statement was found to be a very convenient method of entering data into the
Computer.
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