# Thread: Annuity

1. ## Annuity

How much was spent in interest between the outstanding principle after 5 years, and the outstanding Principle after 10 years.

on a 225,000 loan.
interest rate: 4.948 %
a 30 year mortgage.
principle outstanding after 5 years = $20,6462.32 principle outstanding after 10 years =$18,2731.88

just a bit stuck on what formuals to use... and what values to input.

any help would be great!

2. Rule of Thumb: If you cannot remember which formula to use, then you have not learned the material in any useful way. Sorry, but formula-based concepts are not good. Formulas only work on problems designed to meet their assumptions. Think about the structure and dissect it. There is no formula for that.

In this case, we paid down the loan $206,462.32 -$182,731.88 = $23,730.44 How much was paid in that same period? A 30 year mortgage is likely to be monthly, so that's the last piece. We can calculate the payment and see what happens. You SHOULD be able to use either the 5-year value or the 10-year value or the original value to calculate the payment amount. (I found them to be within 1¢ of each other) Please do that to find the payment, p. Then calculate 60*p -$23,730.44 to answer the question.

3. Originally Posted by TKHunny
Rule of Thumb: If you cannot remember which formula to use, then you have not learned the material in any useful way. Sorry, but formula-based concepts are not good. Formulas only work on problems designed to meet their assumptions. Think about the structure and dissect it. There is no formula for that.

In this case, we paid down the loan $206,462.32 -$182,731.88 = $23,730.44 How much was paid in that same period? A 30 year mortgage is lokely to be monthly, so that's the last piece. We can calculate the payment and see what happens. You SHOULD be able to use either the 5-year value or the 10-year value or the original value to calculate the payment amount. (I found them to be within 1¢ of each other) Please do that to find the payment, p. Then calculate 60*p -$23,730.44 to answer the question.
TKHunny is absolutely right, to paraphrase Newton, "The mechanical mathematician at the slightest hint of change will be left in limbo".