please help me solve this problem.

Answer each of the next questions relating to productivity and costs. i) In an industry, cost per ton of product us known to be $50 for a plant with capacity of 10 tons oer cay, $40 for a plants with capacity 20 tons per day, $30 for a plant with capacity of 30 tons per day. $25 for a plant with capacity of 40 tons per day and $22 for a plant capacity of 50 tons per day. From this information, can we infer decreasing returns to scale, diminishing returns, or economies of scale over the range 10 to 50 tons per day. Based on this information, what plant size is the minimum efficient scale? ii) At an assembly plant, managers use a progress ratio of 0.8. Currently, workers have assembled 100,000 units of the product and the variable cost per unit is $500. What is the expected variable cost per unit for the 400,000th product assembled? Why