I am guessing you are talking about Option 3. They start with $125. So they times it by 1.25 as we are using the multiplier method. So in the First month, it will be 156.25. Second it will be 195.3125. So in August it will be $476.837157. Of couse round it and you will get $476.84.
I believe there is a more efficent way of doing this but I have forgotten.
