A firm employs three factors of production: capital, land and labour. The table below shows how the firm's output is affected by changing the amount employed of these factor inputs.
| Units of output | Units of capital | Units of land | Labour (Number of workers) |
|---|---|---|---|
| 200 | 10 | 15 | 30 |
| 600 | 40 | 60 | 120 |
| 1200 | 80 | 120 | 240 |
| 1800 | 100 | 150 | 300 |
| 2400 | 150 | 225 | 450 |
The firm experiences constant returns to scale when it increases its output from
200 to 600 units.
600 to 1200 units.
1200 to 1800 units.
1800 to 2400 units.
