How do you calculate interest rate if the PV, FV, and time are known?

Question

PV being present value, FV future value and time. Also, how would one figure out the amount of time it takes for an amount to reach a certain amount...let's say $400 to 1,000 at an interest rate of 4?

Answer 1

400*(1.04^N)=1000
1.04^N=2.5
LN1.04^N=N*LN1.04=LN2.5
N=LN2.5/LN1.04=.916291/.039221
=23.36 years

Answer 2

Future Value = Present Value*(1 + Interest rate )^t

so take the present value and multiply it by 1 plus the interest rate (4% = .04 ) raised to the power of the # of years

example:

PV = 500
interest rate = 5%
invested for 5 years

500*(1.05)^5 = $638.14

for your other question.....

PV=400
FV=1,000
interest=4%

1000=400(1.04)^X

solve for the exponent "X"

Answer 3

Using a financial calculator HP-12C
400 CHS PV
1000 FV
4 i
N=24 years if componding yearly with a 4% interest rate
For interest rate
400 CHS PV
1,000 FV
Enter number of years N
Hit i and then rate will appear for yearly