marginal cost (MC) is above average cost (AC), the average cost rises, that is, the marginal cost (MC) pulls the average cost (AC) upwards.
(ii) When marginal cost (MC) stands equal to the average cost (AC), the average cost remains the same, that is, the marginal cost pulls the average cost horizontally.
(iii) if the marginal cost (MC) is below the average cost (AC); average cost falls, that is, the marginal cost pulls the average cost downwards.
