“Find the values of x and y when the smaller triangle here has the given area! “ I'm really confused can someone just show me how to complete one of these problems? I just need one example not all of them, thank you!!!

At the beginning of 1974/75,2 years a man invested #2000 in a bank at 12.5% compound interest, if it degree #650 at the end of each two years to pay his son's school fees, after payment of interest to pay his son's school fees, how much did he have left at the beginning of the 1978/79 school year?