A man invests $40 a week in a superannuation fund. The interest rate for the first 10yrs is 10%pa and for the remaining 20yrs the rate is 12%pa If the interest is worked out monthly, how much is the investmnt worth after 30 years

Hi Could someone please show me how to do this question? Ive only encountered the very easy questions so i have no idea how to do this one...