Question

You can work no more than 60 hours each week at your two jobs. Dog walking pays $7 per hour and your sales job at Computers & More, Inc. pays $12 per hour. You need to earn at least $450 each week to pay your bills. Your friend solves the system of inequalities and tells you that a possible solution is (-3, 50). Is this a possible solution, why or why not?

Answer 1

No

Explanation:

You cannot work negative 3 hours, it's impossible. One possible solution would be to work 50 hours a week at dog walking for 7 dollars an hour, and 10 hours a week at Computers & More, Inc. for 12 dollars a week. This would give you 350 dollars from dog walking, and 120 dollars from Computers & More, Inc. This would be a total of 470 dollars.

Answer 2

No, this is not a possible solution because it does not satisfy all inequalities of the system.

Explanation:

Let x represents the number of hours spent on dog walking and y represents the number of hours spent on sales job at Computers & More Inc.,

Given,

Total hours can not be no more than 60 hours,

⇒ x + y ≤ 60

Dog walking pays $7 per hour and your sales job at Computers & More, Inc. pays $12 per hour.

Thus, the total earning = 7x + 12y

According to the question,

Total earning ≥ $ 450

⇒ 7x + 12y ≥ 450

Also, hours can not be negative,

⇒ x ≥ 0; y ≥ 0

Hence, the system of inequalities that shows the given situation is,

7x + 12y ≥ 450;

x + y ≤ 60;

x ≥ 0; y ≥ 0

Since, -3 ≥ 0 ( False ),

Thus, the point is not satisfying all inequalities of the system,

Hence, it can not be the solution.