SOLUTION: you are getting ready to move and have asked some friends to help. For Lunch, you buy the following sandwiches at the local deli for $30: six tuna sandwiches and six turkey sandwic

Algebra ->  Expressions-with-variables -> SOLUTION: you are getting ready to move and have asked some friends to help. For Lunch, you buy the following sandwiches at the local deli for $30: six tuna sandwiches and six turkey sandwic      Log On


   

Question 1008186: you are getting ready to move and have asked some friends to help. For Lunch, you buy the following sandwiches at the local deli for $30: six tuna sandwiches and six turkey sandwiches. Later at night, everyone is hungry again and you buy for tuna sandwiches and eight turkey sandwiches for 30.60. What is the price of each tuna?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +x+ = price of a tuna sandwich
Let +y+ = price of a turkey sandwich
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(1) +6x+%2B+6y+=+30+
(2) +4x+%2B+8y+=+30.6+
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(1) +x+%2B+y+=+5+
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(2) +40x+%2B+80y+=+306+
(2) +20x+%2B+40y+=+153+
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Multiply both sides of (1) by +20+
and subtract (1) from (2)
(2) +20x+%2B+40y+=+153+
(1) +-20x+-+20y+=+-100+
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+20y+=+53+
+y+=+2.65+
and
(1) +x+%2B+y+=+5+
(1) +x+%2B+2.65+=+5+
(1) +x+=+2.35+
-----------------
A tuna sandwich costs $2.35
check:
(2) +4x+%2B+8y+=+30.6+
(2) +4%2A2.35+%2B+8%2A2.65+=+30.6+
(2) +9.4+%2B+21.2+=+30.6+
(2) +30.6+=+30.6+
OK