Consuelo Chua, Inc

Consuelo Chua, Inc., is a disk drive manufacturer in need of an aggregate plan for July through December. The company has gathered the following data given in the tables. There are 8 hours of production per day, 
You manage a consulting firm down the street from Consuelo Chua, Inc., and to get your foot in the door, you have told Mr. Chua that you can do a better job at aggregate planning than his current staff. He said, "Fine. You do that, and you have a i-year contract," To make good on your boast, you propose a new strategy. Hire 5 workers in August and 5 more in October, and subcontract to meet the rest of the demand. What will be the cost of this strategy? 
Costs    
Holding cost $9/disk drive/Month 
Subcontracting $80/disk drive
Regular-time labor $12
Overtime labor $18/hour (above 8 hours)
Hiring cost $40/worker
Layoff cost $80/worker

Other data
Current workforce (June) 8 people  
Labor-hours/disk drive 4 hours     
Workdays/month-__ 20 days      
Beginning Inventory--a--- 150disk dtives   
Ending Inventory --'----- 0 (risk drives -_     
*Note that there is no holding cost for June.

 Fill in the table below. (enter all responses as whole numbers. In the hire/fire column, use positive numbers for hires -- plus signs omitted: negative numbers for layoffs.) 

Month Demand Beginning  Inventory Units Produced Personnel Staff  Hire/ Layoff   Ending Inventory 
0 June 
1 July 420 
2 August 500 
3 September 450 
4 October 650 
5 November 800 
6 December 680