Harriet Marcus is concerned about the financing of a home. She saw a small cottage that sells for $54,000. Assuming that she puts 19.5% down, what will be her monthly payment and the total cost of interest over the cost of the loan for each assumption? (Do not round intermediate calculations. Round your answers to the nearest cent.)

I am trying to find the monthly payments and total cost of interest for

a. 25 years, 7.00%

b. 25 years, 6.5%

c. 25 years, 6.00%

d. 25 years at 5.5%

and then the the savings in interest cost between 5.50 and 7%

as well as if harriet uses 40 years instead of 25 for both 7% and 5.5 what is the difference in interest