Question

Starting Out with Python 4th ed., Page 104 Programming exercise #14

When a bank account pays compound interest, it pays interest not only on the principal amount that was deposited into the account, but also on the interest that has accumulated over time. Suppose you want to deposit some money into a savings account, and let the account earn compound interest for a certain number of years. The formula for calculating the balance of the account after a specified number of years is:

?=?(1+??)??

A

=

P

(

1

+

r

n

)

n

t

The terms in the formula are:

A is the amount of money in the account after the specified number of years.

P is the principal amount that was originally deposited into the account.

r is the annual interest rate.

n is the number of times per year that the interest is compounded.

t is the specified number of years.

Write a program that makes the calculation for you. The program should ask the user to input the following:

The amount of principal originally deposited into the account

The annual interest rate paid by the account

The number of times per year that the interest is compounded (For example, if interest is compounded monthly, enter 12. If interest is compounded quarterly, enter 4.)

The number of years the account will be left to earn interest

Once the input data has been entered, the program should calculate and display the amount of money that will be in the account after the specified number of years.

All money should be limited to 2 decimal places.

Demo

Note: Bold text indicates user input

Enter principal: 1000

Enter rate: 9.5

Enter number of times per year interest is compunded: 4

Enter number of years: 7

Account balance: $1929.43

eof

Answer 1

IDE used: Pycharm

Note: the formula given in the question is A=P(1+rn)^nt but the correct formula is A= P(1+r/n100)^nt

Program

import math as m         #for pow() function

#getiing inputs from user
p = float(input("Enter the principal amount (upto 2 decimal place): "))
r = float(input("Enter the annual rate of interest: "))
n = int(input("Enter the number of times per year interest is compound: "))
t = int(input("Enter the number of years: "))

#calculating amount using fromula
a = float(p*m.pow((1+r/(100*n)),n*t))

#printing the final amount upto 2 decimal place
print("Account Balance: $%.2f" %a)

Sample Output