The Speedem-Feedem Airline must decide how many new flight attendants to hire and train over the next six months. The requirements, expressed in attendant-hours needed, are tabled below:
|
Month
|
Jan
|
Feb
|
March
|
April
|
May
|
June
|
|
Hours
|
8000
|
9000
|
8000
|
10000
|
9000
|
12000
|
It takes a month of training before an attendant may be put on regular flight duty. During that month the trainee requires 100 hours of training by a regular flight attendant so that each trainee reduces the number of regular attendant flight hours by 100. Each regular attendant works up to 150 hours per month and Feedem-Speedem has 60 regular attendants available at the beginning of January. If regular attendant flight hours available exceed the requirements in a given month other duties are assigned and the attendants are not laid off. At the end of each month 10% of the experienced attendants quit or leave to form a start-up. An experienced attendant costs the company $5000 per month in salary and benefits. A trainee costs $2500. Let xt be the number of attendants hired each month where t=1 for January. There are 60 regular attendees and no trainees present at the beginning of January. Formulate and solve the LP to find the least cost values of xt (t=1...6) that satisfy the demand. Don't worry about fractional solutions.