Nokia sells a new budget cell phone.  Based on information provided by the accounting department, the average variable cost is:  AVC = $30 + Q
The average fixed cost is: AFC = $9,000,000/Q where Q is the number of phones.  The phone sells for $50.
Show your work/thought process:
a. Find the total cost, average cost, and marginal cost equations.
b. At what level of output is average total cost minimized?