Answer:
Down Payment = 5% of 168,000. You finance 95% of 168,000 which is the PV of your payments.
Use the same annuity formula as in your student loan question with monthly rate = 7%/12 and t=12*30 =360 months. That will give you your payment amount.
you will make 360 payments so total Payments = 360*pmt. Total Payments less principal = total interest paid.
