Final answer:
The interest rate for an investment of $2500 that grew to $3425 in 6 years with quarterly compounding is approximately 4.55%.
Step-by-step explanation:
To determine the interest rate of the compounded investment, we can use the formula for compound interest which is A = P(1 + r/n)^(nt), where:
A is the amount of money accumulated after n years, including interest.
P is the principal amount (the initial amount of money).
r is the annual interest rate (decimal).
n is the number of times that interest is compounded per year.
t is the time the money is invested for in years.
Given that the initial investment (P) is $2500, the current value (A) is $3425, the interest is compounded quarterly (n = 4), and the time period (t) is 6 years, we can set up the equation as follows:
3425 = 2500(1 + r/4)^(4*6)
Dividing both sides by 2500 gives us:
1.37 = (1 + r/4)^(24)
We then take the 24th root of both sides to solve for (1 + r/4):
(1 + r/4) = 1.37^(1/24)
To find r, we subtract 1 from both sides and then multiply by 4:
r = [1.37^(1/24) - 1] * 4
Using a calculator, we find that r = 0.0455 or 4.55%
Therefore, the quarterly compounded interest rate that led to a current value of $3425 from a $2500 investment 6 years ago is approximately 4.55%.