Monica planned to buy a house but could afford to pay only $7,000 at the end of every 6 months for a mortgage with an interest rate of 4.20% compounded semi-annually for 25 years. She paid $27,250 as a down payment.

a. What was the maximum amount she could afford to pay for a house?

b. What was her total investment through the mortgage period (not taking the time-value of money into account)?

c. What was the total amount of interest paid through the mortgage period?