I need the answer as soon as possible

A company is planning work force and production level for four months. Company has 20 workers. The forecast for four months for a particular unit is Month Predicted Units Working days June 1280 20 July 640 24 August 900 18 September 1200 26 There are 500 units left over from December and company would like to have 300 units for month of October Assume: cost of hiring one worker $300, cost of firing one worker S1000, and cost of the holding inventory is $300. It was shown that 30 worker produce 330 units of the product during 25 working days. Determine total cost using: (a) Zero-inventory method, (b) Constant work-force method