6. the president of hill enterprises, terri hill, projects the firm's aggregate demand requirements over the next 8 months as follows: january 1,400 may 2,200 february 1,500 june 2,100 march 1,800 july 1,800 april 1,800 august 1,800 her operations manager is considering a new plan, which begins in january with 200 units of inventory on hand. stockout cost of lost sales is $150 per unit. inventory holding cost is $40 per unit per month. ignore any idle-time costs. the plan is called plan a. plan a: vary the workforce level to execute a strategy that produces the quantity demanded in the prior month. the december demand and rate of production are both 1,600 units per month. the cost of hiring additional workers is $60 per unit. the cost of laying off workers is $85 per unit. evaluate this plan. (enter all responses as whole numbers.) note: both hiring and layoff costs are incurred in the month of the change. for example, going from 1,600 in january to 1,400 in february incurs a cost of layoff for 200 units in february. period month demand production hire (units) layoff (units) ending inventory stockouts (units) 0 december 1,600 1,600 200 1 january 1,400 1,600 2 february 1,500 1,400 3 march 1,800 1,500 4 april 1,800 1,800 5 may 2,200 1,800 6 june 2,100 2,200 7 july 1,800 2,100 8 august 1,800 1,800 the total cost of hirings = $ . (enter your response as a whole number.) the total cost of layoffs = $ . (enter your response as a whole number.) the total inventory carrying cost = $ . (enter your response as a whole number.) the total stockout cost = $ . (enter your response as a whole number.) the total cost, excluding normal time labor costs, is = $ . (enter your response as a whole number.)