You have a plant that produces copiers for sale. Your costs for producing copiers are 1: $42, 2: $44, 3: $47, 4: $50, 5: $54, 6: $60, 7: $69, and 8: $80. What are your marginal costs for each copier produced? If you sell a copier for $15 per copier, what quantity of copiers sale would you want?