# Math Help - another interest theory: present value

1. ## another interest theory: present value

Q: Calculate the total present value of the following payments:
$600 made at the end of each of the years 1 to 8$900 made at the end of each of the years 9 to 15
if the annual effective interest rate is 7.5% for the first ten years and 9% thereafter.

I tried to use the present value formula:

PV = X(1+i)^-t

but dun know if it's right or wrong, and does the question have anything to do with the force of interest?

2. Originally Posted by suedenation
Q: Calculate the total present value of the following payments:
$600 made at the end of each of the years 1 to 8$900 made at the end of each of the years 9 to 15
if the annual effective interest rate is 7.5% for the first ten years and 9% thereafter.

I tried to use the present value formula:

PV = X(1+i)^-t

but dun know if it's right or wrong, and does the question have anything to do with the force of interest?