Important Supply Equations/Notes

Fixed Costs: A cost that does not change no matter how much is produced (Ex. Salary, car payments)
Variable Costs: A cost that fluctuates depending on how much is produced (Ex. Electricity, water bill)
Marginal Costs: A cost of producing one more additional unit of a good (Ex. Tshirts)

Total Cost=Fixed Cost+Variable Cost
AFC= TFC/Q
AVC= TVC/Q
ATC= TC/Q or AFC+AVC
Marginal Cost= New TC-Old TC

Example: