1. The problem asks to determine if James has paid too much tax or not enough, and to calculate the refund or liability. 2. To solve this, first find the total tax James owes, which is the sum of his tax payable (from part b) and the Medicare levy (from part c). 3. Then compare this total tax owed to the amount his employer has already sent to the ATO, which is 20000. 4. If the amount sent (20000) is greater than the total tax owed, James has paid too much and is due a refund. Calculate the refund by subtracting the total tax owed from 20000. 5. If the amount sent is less than the total tax owed, James owes more tax. Calculate the liability by subtracting 20000 from the total tax owed. 6. This comparison will tell you whether James has a refund or a tax liability and the amount of it.