SOLUTION: At a cartain snack bar, a mango shake costs twice as much as slice of pizza.If 2 mango shakes ang 3 slices of pizza costs 90,how much is a mango shake?

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: At a cartain snack bar, a mango shake costs twice as much as slice of pizza.If 2 mango shakes ang 3 slices of pizza costs 90,how much is a mango shake?       Log On


   

Question 1066687: At a cartain snack bar, a mango shake costs twice as much as slice of pizza.If 2 mango shakes ang 3 slices of pizza costs 90,how much is a mango shake?
Answer by math_helper(2461) About Me  (Show Source):
You can put this solution on YOUR website!
Let m=the cost of mango shake
Let p=the cost of slice of pizza
—
   m = 2p          (1)
   2m+3p = 90      (2)

(1) allows us to substitute "2p" for "m" in (2):

      2(2p) + 3p = 90
         4p + 3p = 90
              7p = 90
               p = 90/7  

    m = 2p = 2(90/7) = 180/7
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Ans:  A mango shake costs 180/7  (in whatever units of currency are specified).
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Check:   (180/7)*2 + (90/7)*3 = (360/7)+(270/7) = 630/7 = 90  (ok)