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a student government organization is selling christmas trees as a fundraiser. on friday, they sold five noble fir trees and three douglas fir trees for a total of $420. on saturday, twelve noble fir trees and 9 douglas fir trees were sold for a total of 1080. what is the cost per tree of each type

Respuesta :

Answer:

$60 for a noble fir, and $40 for a douglas fir

Step-by-step explanation:

Let x represent the number of noble fir trees

Let y represent the number of douglas fir trees

We can set up a system of equations to solve this problem

5x + 3y =  420  

12x + 9y = 1080      

We can use elimination method to solve this.  9 is a multiple of 3, so we'll multiply the first equation by -3 to get...

-15x - 9y = -1260

12x + 9y = 1080

Now add them together...

-3x = -180         now solve for x...

        x = 60

If x = 60, them

5(60) + 3y = 420        now solve for y

  300 + 3y = 420

      3y = 120

           y =  40

       

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