Sandra's Sweaters' production function is shown in the above table. Sandra rents three knitting machines for $30 a day each and hires workers at a wage rate of $40 a day. If Sandra produces 18 sweaters per day, what is her average total cost?

If a firm sells 20 units of output at $15 per unit and 21 units of output when price is reduced to $14, its marginal revenue from selling the last unit is

A) $6. B) $21. C) $294. D) -$6.

Sometimes, the taxes with the smallest excess burden are

A. progressive. B. regressive. C. proportional. D. digressive.