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Eight hot dogs and seven hot dog rolls cost $13.60 . Seven hot dogs and eight hot dog rolls cost $13.40. How much, in cents, is the positive difference of the costs of a hot dog and a hot dog roll?

 Sep 9, 2018
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Let x = hot dog price  and y = roll price,   then according to the question :

8x + 7y = 13.60     and

7x + 8y = 13.40             

     Now solve for x and y     and then find the difference between them......there are multiple ways to do this

 

Let's subtract the first eqaution from the second one

 

7x-8x  +   8y-7y  = 13.40-13.60

-x  +y  = -.20     Multiply both sides by -1

 

or   x-y = .20           The difference between a hot dog and a roll is .20

 Sep 9, 2018
edited by ElectricPavlov  Sep 9, 2018

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