Economics (attempted as suggested by economyst)
posted by eStone .
Posted by eStone on Sunday, March 29, 2009 at 5:47pm.
Suppose that a firm is currently employing 30 workers, the only variable input, at a wage rate of $60. The average product of labor is 30, the last worker added 12 units to total output, and total fixed cost is: $3,600.
a. What is marginal cost?
b. What is average variable cost?
c. How much output is being produced?
d. What is average total cost?
e. Is average variable cost increasing, decreasing or constant? What about average total cost>
Responses
* Economics  economyst, Monday, March 30, 2009 at 9:42am
Do a little research and then take a shot. What do you think?
Hint. All of these questions need simple algebra.
Repost, and I or others will check your answers.
Here's my guess:
a. Marginal Cost
 change in TC/change in Q
so... 3600/12 = 300??
b. Average variable cost
 TVC/Q
so... i'm not sure how to find TVC, is it 20*60 = 1200, which would then mean 1200/600 = 2? But i'm not sure if 2 is too low for AVC?
c. Output = 20*30 = 600
d. ATC
 TC/Q
I'm not sure how to find total cost, but can I just use TFC and do 3,600/600 = 6? (then again that might be a little low for ATC :(
e. AVC would be increasing if each worker adds more output? and ATC would be inceasing as well?
Sigh, I hope my answers don't make me look stupid, I feel way over my head here, but thanks for the help in advance.

a. 60
b. 60
c. 30*30+12=912
d. atc= (3600+60*30)/30=180
e. increasing, decreasing 
Dont look at Robert's answers. He got them all wrong.
a) The firm paid the last hired worker $60 and he produced 12 units. So, cost of producing the last unit (MC) is 60/12 = $5
b) The firm hires 30 workers and pays them $60 each, so Total variable costs are 30*60 = 1800. On average, a worker makes 30 units, so total units are 30*30 = 900. Soooo, the average variable cost of producing a unit (AVC) is = 1800/900 = 2.
c) 900 from b)
d) Total fixed costs are total variable costs (1800) plus total fixed costs (given at $3600). So, TC = 3600+1800 = 5400. Average total costs = TC/Q = 5400/900 = 6.
e) Since the marginal (last) worker added 12 unit and the overall average is 30 units, average variable costs must be rising. If AVC is rising, TVC must also be rising. 
Wow! Economyst, thank you for explaining it! Now that I read and look at the numbers it makes more sense, I definitely have clarification. You made it seem so simple, I guess I just need to calm down and do what the equations say. I appreciate it, this is going to help me study a lot for my exam.

a. SMC= w/MP = 60/12 = $5
b. AVC= w/AP = 60/30 = 2
c. OUTPUT (Q)= AP*L = 30*20 = 600
d. ATC= AFC + AVC = (3600/600) + 2 = 8