Question

Solve using Raptor. Kim wants to buy a car. Help Kim compute the monthly payment on a loan, given the loan amount, the annual percentage rate of interest, and the number of monthly payments. The program should allow Kim to input the loan amount, interest rate, and how many payments she wants to make. It should then compute and display the monthly payment.

                   

You will need the following variables:

                   

		Payment        LoanAmt         InterestRate
		MonthlyRate    NumberMonths

                   

You will need the following formulas:

                   

		MonthlyRate = InterestRate/1200

                   

Note: when the user enters InterestRate as a percentage, it must be divided by 100 to make it a decimal (i.e., 18% = 18/100 = 0.18). The InterestRate offered by car dealers is an annual rate so this must be divided by 12 to get the MonthlyRate. The formula given above combines the two steps (i.e., annual rate of 18% = 18/100 = 0.18 and the monthly rate is 0.18/12 = 0.015 or 18/(100*12) = 18/1200.

                   

		Payment = LoanAmt * MonthlyRate * (1 + 
		           MonthlyRate)^NumberMonths ÷ ((1 +
		           MonthlyRate)^NumberMonths – 1)

                   

Note: The formula must be entered carefully, exactly as shown.

Answer 1

/************************************BuyCar.java********************************/
import java.text.DecimalFormat;
import java.util.Scanner;
public class BuyCar {
   public static void main(String[] args) {
       Scanner scan = new Scanner(System.in);
       DecimalFormat f = new DecimalFormat("#.##");
       System.out.print("Enter the loan amount:");
       double loanAmount = scan.nextDouble();
       System.out.print("Enter the interest rate: ");
       double interestRate = scan.nextDouble();
       System.out.print("How many payment you want to make: ");
       int numberOfPayment = scan.nextInt();
       double monthlyRate = interestRate / 1200;
       // This is your formula
       double payment1 = (loanAmount * monthlyRate)
               * (Math.pow((1 + monthlyRate), numberOfPayment) / (Math.pow(1 + monthlyRate, numberOfPayment) - 1));
       // The same formula you can use
       double payment = (loanAmount * monthlyRate) / (1 - Math.pow(1 + monthlyRate, -numberOfPayment));
       System.out.println("Each month payment is: " + f.format(payment));
       System.out.println("Each month payment by your formula: " + f.format(payment1));
   }
}

/**********************output*****************************/

Enter the loan amount:20000
Enter the interest rate: 8
How many payment you want to make: 12
Each month payment is: 1739.77
Each month payment by your formula: 1739.77