For simplicity, I added two additional columns. One for the total fixed cost and one for the total variable cost. The first step is to calculate the fixed and variable costs for every quantity. Fixed costs are unchanged with output while variable costs are directly related to changes in output. So when the quantity is zero, the total cost is equal to the fixed cost (800). Therefore, the total fixed cost is equal to 800 for all output levels. Next to find the total variable cost, simply subtract the fixed cost from the total cost for every output level.

The marginal cost is the additional cost of an additional unit and can be calculated by change in total cost divided by the change in output. Finally, the average costs are calculated by dividing the total by the quantity. Below is the calculations for the first unit and the table below is filled in using these methods.

TC=FC+VC1000=800+VCVC=200andMC=ΔTCΔQMC=1000−8001−0MC=2001MC=200andAFC=FCQAFC=8001AFC=800andAVC=VCQAVC=2001AVC=200andAC=TCQAC=10001AC=1000TC=FC+VC1000=800+VCVC=200andMC=ΔTCΔQMC=1000−8001−0MC=2001MC=200andAFC=FCQAFC=8001AFC=800andAVC=VCQAVC=2001AVC=200andAC=TCQAC=10001AC=1000