A firm can manufacture a product according to the production function Q=3K^1/2L^1/2, and capital is fixed at 4.

1.When the firm hires 16units of labor,the average product of labor is (?)

2. When the firm hires16units of labor,the marginal product of labor is (?)

3. If the firm can sell its output at a price of $10 per unit and can hire labor at $10 per unit, it should hire (?)units of labor to maximize the profits.