Calculate the Average Product of Labour (APL) for 1, 3, and 4 employees, given their respective outputs. Will the firm recruit a fifth employee if their output is the same as with four employees?

The firm's output with 4 employees is 680. With 5 employees, the output remains 680. This means the marginal product of labour for the fifth employee is zero ($680 - 680 = 0$). A rational firm will not hire an additional employee if that employee does not contribute to increasing total output, as it would only increase costs without increasing revenue.