Determine the rate of return if the present value of an investment is $12000 and the future value was $18000.?

i = (FV / PV)^(1 / n) - 1

if n = 1

i = (18000 / 12000)^(1 / 1) - 1 = 50%

Assuming that the interest is compounded once a year:
Future value 18000
Principal amount 12000
Number of years 1
Number of times compounded per year 1
Amount after 1 years : A = P (1+r/t)^nt
Amount after 1 years 18000 = 12000 ( 1 + r / 1)^(1)(1)
18000 = 12000 ( 1 + r / 1)^1
18000 / 12000 = ( 1 + r / 1)^1
1.5 = ( 1 + r / 1)^1
Take logarithm of both sides
ln (1.5) = 1 ln ( 1 + r / 1)
0.4054651081081644 = 1 ln ( 1 + r / 1)
0.4054651081081644 = ln ( 1 + r / 1)
e^0.4054651081081644 = ( 1 + r / 1)
1.5 = ( 1 + r / 1)
0.5 = r / 1
r = (1)(0.5) = 0.5
rate = 50 %

a