Mrs. Green saved a sum of money, $AU X, into her fixed deposit bank account. She then decided to put in another $AU 70,000 into her bank account after leaving the money in the bank for 6 full years. Mrs. Green’s fixed deposit bank account has about $AU 311,664.81 in total at the end of the tenth year of her savings. Assume that the bank gives an average interest rate of 3.5% per annum for fixed deposit accounts, calculate X.