I can't seem to get the answer for part a, since there isn't any MC value that equates to MR.

Tenzin hire workers to operate a machine to produce a product Y that sells in the market at $4 per unit. The wage of a worker is $40 per day and the rental price of a machine is $40 per day. The company also rents a factory at $20 per day to produce Y. The quantity of Y it produces varies with the number of workers it hires per day, as shown in the table below: Number of Workers per Day Quantity of X 0 0 20 60 130 160 168 172 a. Determine the optimal output of Tenzin. At this output, compute the profit or loss of Tenzin. b. If the rent of the factory increases to $40 per day, determine the optimal output of Tenzin. At this output, compute the profit or loss of Tenzin. c. Assume that the rent of the factory is $20 per day, but the government imposes production tax of $1 per unit of Y. Determine the optimal output of Tenzin. At this output, compute the profit or loss of Tenzin