00:01
In this problem, we amortize a home loan of $80 ,000, a 7 .2 % compounded monthly for 20 years, with equal monthly payments of $629 .88.
00:11
Our job is to find the unpaid balance after one year and to determine the amount of interest paid in the first year.
00:18
We will need the present value formula.
00:21
Here's that formula where p is the present value.
00:24
R is the regular payment.
00:26
I is the periodic interest rate, and n is the number of payments.
00:29
So after one year, there are still 19 years of payments to be made.
00:33
So n is 12 times 19 or 228.
00:35
The periodic interest rate turns out to be 0 .006, and r is $62988 in dollars.
00:44
So p, using the formula, is found by multiplying r times that expression in brackets.
00:53
We'll make some room for that in just a second.
00:57
So we will substitute the given values.
01:00
So let's come in here so you can see that.
01:02
Better.
01:04
There we go...