Planners for a company that makes several models of skateboards are about to prepare the aggregate plan that will cover six periods. They have assembled the following information:

Period	1	2	3	4	5	6	Total
Forecast	200	200	300	400	500	200	1,800

Costs
Output
Regular time	=	$	8	per skateboard
Overtime	=	$	10	per skateboard
Subcontract	=	$	10	per skateboard
Inventory	=	$	4	per skateboard per period on average inventory
Back orders	=	$	5	per skateboard per period

They have learned that one person is about to retire from the company. The reduced regular-time output is 280 units per period. Prepare a plan that minimizes cost using subcontracting at a maximum rate of 50 units per period as needed with no overtime. Again, plan for a zero inventory balance at the end of period 6. (Negative amounts should be indicated by a minus sign. Leave no cells blank - be certain to enter "0" wherever required. Omit the "$" sign in your response.)

Period	1	2	3	4	5	6	Total
Forecast	200	200	300	400	500	200	1,800
Output
Regular	280	280	280	280	280	280	1,680
Subcontract	0	0	20	50	50	0	120
Output-
Forecast	80	80	0	-70	-170	80
Inventory
Beginning	0	80	160	160	90	0
Ending	80	160	160	90	0	0
Average	40	120	160	125	45	0	490
Backlog	0	0	0	0	80	0	80
Costs:
Regular	$ 2,240	2,240	2,240	2,240	2,240	2,240	$ 13,440
Subcontract	0	0	200	500	500	0	1,200
Inventory	160	480	640	500	180	0	1,960
Backorder	0	0	0	0	400	0	400
Total	$ 2,400	2,720	3,080	3,240	3,320	2,240	$ 17,000

Part 2:A manager is attempting to put together an aggregate plan for the coming nine months. She has obtained a forecast of expected demand for the planning horizon. The plan must deal with highly seasonal demand; demand is relatively high in periods 3 and 4 and again in period 8, as can be seen from the following forecasts:

Period	1	2	3	4	5	6	7	8	9	Total
Forecast	190	230	260	280	210	170	160	260	180	1,940

The department now has 20 full-time employees, each of whom can produce 10 units of output per period at a cost of $8 per unit. Inventory carrying cost is $9 per unit per period, and backlog cost is $13 per unit per period.

Suppose another option is to use part-time workers to assist during seasonal peaks. The cost per unit, including hiring and training, is $10. The output rate is 10 units per worker per period for all workers. A maximum of 10 part-time workers can be used, and the same number of part-time workers must be used in all periods that have part-time workers. The ending inventory in period 9 should be 10 units. The limit on backlogs is 20 units per period. Try to make up backlogs as soon as possible. Compute the total cost for this plan. Assume 20 full-time workers. (Omit the "$" sign in your response.)

Total cost

$