Question

A print shop at a community college in Cupertino, California, employs two different contractors to maintain its copying machines. The print shop needs to have 12 IBM, 18 Xerox, and 20 Canon copying machines serviced. Contractor A can repair 2 IBM, 1 Xerox, and 2 Canon machines at a cost of $800 per month, while Contractor B can repair 1 IBM, 3 Xerox, and 2 Canon machines at a cost of $1000 per month. What is the minimum cost to employ the contractors? Round your answer to the nearest whole number. Do not include a dollar sign or comma in your answer.

Answer 1

$8800

Explanation:

Let x be the number of months contract A is employed and let y be the number of months contractor B is employed. Since we are trying to minimize cost, our objective function represents the total cost to employ contractor A and contract B. This function is defined by

C(x,y)=800x+1000y

The first constraint is that the company needs to have 12 IBM copying machines serviced and we know that contractor A can repair 2 IBM copying machines and contractor B can repair 1 IBM copying machines. This translates into the following inequality.

2x+y≥12

The second constraint is that the company needs 18 Xerox copying machines serviced and we know that contractor A can repair 1 Xerox copy machines while contractor B can repair 3 Xerox copy machines. This translates into the following inequality.

x+3y≥18

The third constraint is that the company needs 20 Canon copying machines serviced and we know that contractor A and contractor B can repair 2 Canon copy machines each. This translates into the following inequality.

2x+2y≥20

The fact that x and y must be positive numbers is represented by the following two constraints:

x≥0,y≥0

Using all of this information, our problem is as follows.

Minimize: C(x,y)=800x+1000y

Subject to: 2x+y≥12

x+3y≥18

2x+2y≥20

x≥0

y≥0

The corner points are:

(0,12),(18,0),(2,8),(6,4)

The point (6,4) gives lowest cost: $8800