Answer:
Economies of scale are the money firm could save, when it expands itself. For example, if firm's average cost per 1 unit is 10 at the output of 100 unit and when it expands its output to 200 unit, the average cost per 1 unit drops to 8, then the firm enjoys economies of scale. So they occur, when a percentage increases equally in all inputs leads to a greater percentage change in output. Inputs are land, labour and capital and output are the goods and services the firm produces