document.write( "Question 205238: Martin purchases 2 apples and 4 oranges. Michelle purchases 8 apples and 2 oranges. If Michelle pays twice as much as Martin. How many apples can be purchased for the price of 9 oranges? \n" ); document.write( "
Algebra.Com's Answer #154919 by Theo(13342)\"\" \"About 
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let cost of apples = x
\n" ); document.write( "let cost of oranges = y
\n" ); document.write( "let b = how much martin pays
\n" ); document.write( "let g = how much michelle pays
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\n" ); document.write( "b = 2x + 4y
\n" ); document.write( "g = 8x + 2y
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\n" ); document.write( "the assumption is that they both pay the same price per apple and the same price per orange.
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\n" ); document.write( "michelle pays twice as much as martin so:
\n" ); document.write( "g = 2*b
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\n" ); document.write( "if g = 2*b then:
\n" ); document.write( "8x +2y = 2*(2x + 4y)
\n" ); document.write( "this becomes:
\n" ); document.write( "8x + 2y = 4x + 8y
\n" ); document.write( "subtract 4x from both sides of the equation and subtract 2y from both sides of the equation to get:
\n" ); document.write( "8x - 4x = 8y - 2y
\n" ); document.write( "which results in:
\n" ); document.write( "4x = 6y
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\n" ); document.write( "the question is:
\n" ); document.write( "how many apples can be purchased for the price of 9 oranges.
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\n" ); document.write( "To find that you need to find the price of oranges in comparison to the price of apples.
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\n" ); document.write( "Since y is the price of oranges, then solve for y in the equation of:
\n" ); document.write( "4x = 6y
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\n" ); document.write( "Dividing both sides of this equation by 6 gets:
\n" ); document.write( "Y = 4x/6 = (2/3)*x
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\n" ); document.write( "The price of 9 oranges would then be 9 * y = 9 * (2/3)*x
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\n" ); document.write( "This results in (18/3) * x
\n" ); document.write( "Which reduces to:
\n" ); document.write( "6*x
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\n" ); document.write( "The price of 9 oranges is 6 apples.
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\n" ); document.write( "One way to check your answer is to place this results in the original equations and see what comes out.
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\n" ); document.write( "The original cost to Martin was:
\n" ); document.write( "2x + 4y
\n" ); document.write( "since y = (2/3)*x then this cost becomes:
\n" ); document.write( "2x + 4*(2/3)*x which becomes:
\n" ); document.write( "2x + (8/3)*x which becomes:
\n" ); document.write( "(14/3)*x
\n" ); document.write( "-----
\n" ); document.write( "the original cost to Michelle was:\"
\n" ); document.write( "8x + 2y
\n" ); document.write( "since y = (2/3)*x then this cost becomes:
\n" ); document.write( "8x + (2*(2/3)*x which becomes:
\n" ); document.write( "8x + (4/3)*x which becomes:
\n" ); document.write( "(28/3)*x
\n" ); document.write( "-----
\n" ); document.write( "since michelle paid twice as much as martin, and:
\n" ); document.write( "(28/3)*x is 2 times (14/3)*x, then the equation looks good and you can say with reasonable confidence that the price of 9 oranges is 6 apples.
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