If marginal cost is increasing, average total cost must be increasing

Suppose a fishing boat currently brings 10,000 fish to market and earns a profit of $40,000 when the price of fish is $8 . Suppose the boat dealer had overcharged the boat owner for the boat and refunded the overcharged amount. If the profit increases to $7.50 per fish, what was the value of the refund from the dealer?

a. $2.50 b. $25,000 c. $3.50 d. $35,000 e. $75,000

At Bert's Bootery, the total cost of producing twenty pairs of boots is $400 . The marginal cost of producing the twenty-first pair of boots is $83 . We can conclude that the

a. average variable cost of 21 pairs of boots is $23. b. average total cost of 21 pairs of boots is $23. c. average total cost of 21 pairs of boots is $15.09. d. marginal cost of the 20th pair of boots is $20.