Answer:
Given :Cost function : 

To Find :  Find the average cost per item when the required number of items is produced
Solution:
a) 200 items 
Cost function : 

Substitute x = 200
 


So, Total cost of producing 200 items is 12320
Now Average cost per item = 

 Average cost per item= 

Average cost per item=61.6
So, the average cost per item when 200 items are produced is 61.6 .
b) 2000 items 
Cost function : 

Substitute x = 2000
 


So, Total cost of producing 2000 items is 26000
Now Average cost per item = 

 Average cost per item= 

Average cost per item=13
So, the average cost per item when 2000 items are produced is 13.
c) 5000 items
Cost function : 

Substitute x = 5000
 


So, Total cost of producing 5000 items is 48800
Now Average cost per item = 

 Average cost per item= 

Average cost per item=9.76 
So, the average cost per item when 5000 items are produced is 9.76