document.write( "Question 545690: George decides to mix grades of gasoline in his truck. He puts in 8 gallons of regular and 12 gallons of premium for a total cost of $55.80. If premium gasoline costs $0.15 more per gallon than regular, what was the price of each grade of gasoline. \n" ); document.write( "
Algebra.Com's Answer #355671 by stanbon(75887)\"\" \"About 
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He puts in 8 gallons of regular and 12 gallons of premium for a total cost of $55.80. If premium gasoline costs $0.15 more per gallon than regular, what was the price of each grade of gasoline.
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\n" ); document.write( "Equations:
\n" ); document.write( "8r + 12p = 55.80
\n" ); document.write( "p = r+ 0.15
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\n" ); document.write( "Substitute for \"P\" and solve for \"r\":
\n" ); document.write( "8r + 12(r+0.15) = 55.80
\n" ); document.write( "8r + 12r + 1.80 = 55.80
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\n" ); document.write( "20r = 54
\n" ); document.write( "regular price = 2.70
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\n" ); document.write( "Solve for \"p\":
\n" ); document.write( "p = r + 0.15
\n" ); document.write( "premium price = 2.85
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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