You didn't specify the periodic payment in your question. I will solve it assuming that payment is made monthly.
Amount owing by Tom = 70% of 139,000 = 0.7 x 139,000 = $97,300
Present Value of an annuity is given by PV = P(1 - (1 + r)^-n)/r; where P is the periodic (monthly) payment, r is the interest rate = 12%/12 = 1% = 0.01, n is the number of periods = 25 x 12 = 300 months.
97,300 = P(1 - (1 + 0.01)^-300)/0.01 P = 973/(1 - (1.01)^-300) = 973/(1 - 0.050534) = 1,024.79 Thus Tom pays $1,024.79 per month.
Interest due for the first month = 0.01 x 97,300 = $973
Therefore, the portion of the first payment that covers the interest is $973
Total = Principal * e ^ (rate * years) where "e" is the mathematical constant = 2.718281828459 ... Total = $820.00 * 2.718281828459 ^ (.05 * 3) Total = $820.00 *
<span>
<span>
<span>
1.1618342427
</span>
</span>
</span>
Total =
<span>
<span>
<span>
952.70</span></span></span>