Suppose that a firm hiring labor in a perfectly competitive factor market increases the quantity of labor from five workers to six workers per day. If the market wage is $100 per day, the marginal factor cost for the sixth worker is $ ?

Now suppose that the firm is a monopsony firm. To increase the quantity of labor from five workers to six workers, the market wage increases from $100 to $120 per day. In this case, the marginal factor cost for the sixth worker is $ ?