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In a certain clothing store, 6 shirts and 3 ties cost $79.50, and 3 shirts and 2 ties cost $41. Determine the cost of each tie.

 Feb 13, 2020
 #1
avatar+129852 
+2

Let x be the cost of a shirt  and y be the  cost of a tie.....so....we have this system of equations :

 

6x + 3y =  79.50

3x  + 2y = 41

 

Multiply the second equation through by -2  and we have

 

6x + 3y =  79.50

-6x - 4y  = -82        add these 

 

-y=   -2.5

y= 2.5   = $2.50 = the cost of a tie

 

And using   3x + 2y  =41  we can find the cost of a shirt

 

3x + 2(2.50) = 41

3x  + 5 =  41         subtract  5 from both sides

 

3x = 36   divide both sides  by 3

 

x = $12  = the cost of a shirt

 

 

 

cool cool cool

 Feb 13, 2020
 #2
avatar+865 
+1

Let's make s the price for a shirt.

And t the price of a tie:

 

6s + 3t = 79.50

3s + 2t = 41.

 

We can modify the equation by multiplying the second one by -2.

 

-6s - 4t = -82.

 

Solving for t: t = 2.5.

 

Solving for s:

Knowing t, we can solve the equation:

 

3s + 2(2.50) = 41. (I'm using this one because it's easier)

3s + 5 = 41

3s = 36

s = 12

t = 2.5

 

I didn't really know the answer, until I looked at CPhill's, and now I understand the solution and how to do it now. Thanks CPhill!!

 Feb 13, 2020

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