Q. Example on Relationship between marginal and average cost?

This relationship between marginal and average cost can easily be recalled with the aid of Fig. below. It can be seen from figure that so long as MC is below AC, average cost falls which is, MC pulls AC downwards. When MC is above AC, average cost rises, which is, MC pulls AC upwards. When MC equals AC, average cost remains constant, which is, MC pulls AC horizontally. Arrows show the direction of these pulls.

Average and marginal cost

It is to be noted that a rising MC curve also cuts AVC curve at its lowest point. Reason for this is exactly the same as that we have given above to elucidate why MC cuts AC at its minimum point.