Answer;
Total profit is $18000
Explanation:
Given in question 
Number of unit is 1000
Average revenue is $100
Average total cost is $80
Fixed cost is $2000
Total revenue = average revenue 
 number of unit
 number of unit
 Total revenue = $100 
 1000=$100000
 1000=$100000
Total input cost = total cost + fixed cost
Total cost = average cost 
 total unit
 total unit
Total cost =$80 
 1000 = $80000
 1000 = $80000
Total input cost = $80000 + $2000 = $82000
Profit = total revenue-total cost
Profit = $100000 - $82000 = $18000
Total profit is $18000