How to add method() to calculate the monthly repayment amount(product price divided by number of months). Include sub class named finance period, if number of months to pay for product is greater than 3,customer will pay 25% interest else no interest applies, maximum months to pay for product is 12.override the calculate repayment() by determine if customer will pay interest or not and calculate monthly repayment amount. Create customer finance class contains logic to test two classes, prompt user for data for first object where no interest applies and display results and prompt user for data where interest is applicable and display results.