You decide to take out an ordinary interest loan of $30,000 at 4%, on a 90 day note.
a) In 45 days you decide to make a payment of $10,000 on the loan. What is your new principal? Explain how you got the answer.
P = Po + Po*r*t =
30,000 + 30,000*(0.04/360)*45 - 10,000 =
30,000 + 150 -10,000 = $20,150.