Suppose that the amount of capital and plant size are fixed for a firm. With 10 workers, it can produce 180 units of output and with 11 workers, the output produced is 190 units. Which of the following statements is true?

The marginal product of the 11th worker is 18 units.
When the 11th worker is hired, average product of labour is greater than marginal product
The additional unit of labour hired by the firm exhibits increasing returns.
The average product of labour when 10 workers are hired is 10 units.

Explanation
The average product of labour is calculated by dividing total output by the number of workers. This is equal to 190/10 = 19 units. The marginal product of the 11th worker is the additional output produced by the 11th worker, which is equal to 10 units.