Answer:
Per unit total cost $49.00
Explanation:
The per unit total cost is as follows;
Particulars   Total Costs   Output
High level   $21,300      420
Low level   $15,300      270
Difference  $6,000       150
Unit variable cost 40 ($6000 ÷ 150)
Fixed cost $4,500 ($21,300 - (420 × 40) )
Total cost at 500 lenses $24,500 ($4,500 + (500*40))
Per unit total cost $49.00 ($24,500 ÷ 500)