Erykah invests £12000 in an account paying compound interest for 3 years.
In the first year the rate of interest is x%
At the end of the first year the value of Erykah's investment is £12240
In the second and third years the rate of interest is x/2% (it's a fraction idk how to type that!)
What is the value of Erykah's investment at the end of three years?