HP 15c Collector's Edition

46 Section 3: The Memory Stack, LAST X, and Data Storage
2.
Use arithmetic with constants to calculate the remaining
balance of a $1000 loan after six payments of $100 each and a
n
interest rate of 1% (0.01) per payment period.
Procedure: Load the stack with (1 + i), where i
= interest rate,
and key in the initial loan balance. Use the following formula to
find the new balance after each payment.
New Balance = ((Old Balance) × (1 + i)) − Payment
The first part of the key sequence would be:
1.01 v v v 1000
For each payment, execute:
* 100 -
Balance after six payments: $446.32.
3. Store 100 in R
5
. Then:
1.
Divide the contents of R
5
by 25.
2.
Subtract 2 from the contents of R
5
.
3.
Multiply the contents of R
5
by 0.75.
4.
Add 1.75 to the contents of R
5
.
5.
Recall the contents of R
5
.
Answer: 3.2500.
A possible keystroke solution is:
100 O 5
25 O ÷ 5
2 O - 5
0.75 O * 5
1.75 O + 5
l 5