Eliza deposits $8500 in a college fund. If the fund earns an annual simple interest rate of 6.5%, how long must the money be in the fund to earn $9392.50 in interest

Question

mathstudent55 · Answer

The formula for simple interest is

I = prt

where I = interest
p = principal
r = annual interest rate
t = time in years

mathstudent55 · Answer

In your case, the principal is $8500; the rate is 6.5%; the interest is $9392.50; time is unknown.
Plug in all those values in the equation and solve for t.

amigatour · Answer

I would use A=P(1+r/n)^nt 

Since it's asking for t, you should isolate t.

mathstudent55 · Answer

@amigatour 
The problem states simple interest and is looking for the time needed to earn a certain amount of interest. A compound interest formula that calculates the entire future value comprising of principal and interest will not work here.

amigatour · Answer

@mathstudent55: you're right. I calculated it and I got the answer.