SOLUTION: Gina ordered 2 sheets of wallet-sized photos and 4 sheets of portrait-sized photos for $30. Rosanne ordered 3 sheets of wallet-sized photos and 3 sheets of portrait-sized photos fo

Algebra ->  Systems-of-equations -> SOLUTION: Gina ordered 2 sheets of wallet-sized photos and 4 sheets of portrait-sized photos for $30. Rosanne ordered 3 sheets of wallet-sized photos and 3 sheets of portrait-sized photos fo      Log On


   

Question 1148929: Gina ordered 2 sheets of wallet-sized photos and 4 sheets of portrait-sized photos for $30. Rosanne ordered 3 sheets of wallet-sized photos and 3 sheets of portrait-sized photos for $27. Kristina ordered 1 sheet of wallet-sized photos and 5 sheets of portrait-sized photos. Each sheet of wallet-sized photos cost the same. Each sheet of portrait-sized photos cost the same. How much did Kristina pay for her photos?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = cost of 1 sheet of wallet-sized photos
Let +b+ = cost of 1 sheet of portrait-sized photos
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(1) +2a+%2B+4b+=+30+
(2) +3a+%2B+3b+=+27+
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Multiply (1) by +3+
Multiply (2) by +2+
Subtract (2) from (1)
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(1) +6a+%2B+12b+=+90+
(2) +-6a+-+6b+=+-54+
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+6b+=+36+
+b+=+6+
and
(1) +2a+%2B+4b+=+30+
(1) +2a+%2B+4%2A6+=+30+
(1) +2a+=+6+
(1) +a+=+3+
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+1%2A3+%2B+5%2A6+=+3+%2B+30+
She paid $33 for her photos