Suppose a firm produces with a technology that exhibits constant returns to scale at all levels of production. The firm's inputs are workers and laptops. The firm sells its output in a perfectly competitive market. It also hires its inputs (hires workers and rents laptops) in perfectly competitive markets. Assume that in the long run the firm produces y units of output using x1 workers and x2 laptops. If the firm doubles the amount of workers and laptops (using 2x1 and 2x2), we would expect the firm's long-run profits to

In the long run we expect firms to earn zero profits. With competitive markets for both inputs and output, and with constant returns to scale, a doubling of all inputs would lead to twice as much output, twice as much revenue, and twice as much cost.

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