MARGINAL COST EQUATION

The contribution theory explains the relationship between the variable cost and selling price. It
tells us that selling price minus variable cost of the units sold is the contribution towards fixed
expenses and profit. If the contribution is equal to fixed expenses, there will be no profit or
loss and if it is less than fixed expenses, loss is incurred. Since the variable cost varies in
direct proportion to output, therefore if the firm does not produce any unit, the loss will be
there to the extent of fixed expenses. These points can be described with the help of following
marginal cost equation: S × U – V × U = F + P
Where,
S = Selling price per unit
V = Variable cost per unit
U = Units
F = Fixed expenses
P = Profit