Margin Cost
Marginal cost is calculated by dividing the change in total cost by the change in quantity. … Divided by the change in quantity, which is the additional 100 units. That gives us: $90⁄100, which equals $0.90 per unit as the marginal cost.
Formula
\(MC = \frac{\Delta C}{\Delta Q}\) MC = marginal cost {Δ C} = change in cost {Δ Q} = change in quantity