A person invested #6000 at 9% simple interest per year. How long will it be before investment is worth 9000 or more?

Question

A person invested #6000 at 9% simple interest per year. How long will it be before investment is worth 9000 or more?

Answer 1

We Want 6,000*(1+i)^T = 9,000 where i is the interest rate and T is the number of Years..

so 9,000/6,000 = ((1+i)^T = 3/2

Take natural logarithms ofboth sides and get ln(3/2) = T(ln(1+i)

so ln(3/2)/Ln(1.09) = T I will leave you to your calculator to solve