document.write( "Question 1133340: A chef needs 6 L of a solution that is 70% sugar. He has a 30% sugar mixture and an 80% sugar mixture that he can combine to make the 70% mixture.\r
\n" ); document.write( "\n" ); document.write( "Let x represent the number of liters of the 30% sugar mixture and let y represent the number of liters of the 80% sugar mixture.\r
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Algebra.Com's Answer #750541 by Theo(13342)\"\" \"About 
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x = 30% solution
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\n" ); document.write( "\n" ); document.write( "you want 6 liters of a 70% solution.\r
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\n" ); document.write( "\n" ); document.write( "first equation is x + y = 6\r
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\n" ); document.write( "\n" ); document.write( "second equation is .3 * x + .8 * y = .7 * (x + y)\r
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\n" ); document.write( "\n" ); document.write( "in the first equation solve for y to get y = 6 - x\r
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\n" ); document.write( "\n" ); document.write( "in the second equation replace y with 6 - x to get:\r
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\n" ); document.write( "\n" ); document.write( ".3 * x + .8 * y = .7 * (x + y) becomes .3 * x + .8 * (6 - x) = .7 * (x + 6 - x)\r
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\n" ); document.write( "\n" ); document.write( "simplify to get .3 * x + 4.8 - .8 * x = 4.2\r
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\n" ); document.write( "\n" ); document.write( "combine like terms to get: -.5 * x + 4.8 = 4.2\r
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\n" ); document.write( "\n" ); document.write( "subtract 4.8 from both sides of this equation to get -.5 * x = -.6\r
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\n" ); document.write( "\n" ); document.write( "divide both sides of this equation by -.5 to get:\r
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\n" ); document.write( "\n" ); document.write( "x = -.6/-.5 = 1.2\r
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\n" ); document.write( "\n" ); document.write( "in the equation of x + y = 6, replace x with 1.2 and solve for y to get:\r
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\n" ); document.write( "\n" ); document.write( "y = 6 - 1.2 = 4.8\r
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\n" ); document.write( "\n" ); document.write( "x + y = 6 becomes 1.2 + 4.8 = 6 which becomes 6 = 6 which is true.\r
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\n" ); document.write( "\n" ); document.write( ".3 * x + .8 * y = .7 * (x + y) becomes .3 * 1.2 + .8 * 4.8 = .7 * (1.2 + 4.8) which becomes .36 + 3.84 = .7 * 6 which becomes 4.2 = 4.2 which is true.\r
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\n" ); document.write( "\n" ); document.write( "the solution looks good.\r
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\n" ); document.write( "\n" ); document.write( "x = 1.2 and y = 4.8\r
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\n" ); document.write( "\n" ); document.write( "x + y = 6 becomes 1.2 + 4.8 = 6 which is true.\r
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\n" ); document.write( "\n" ); document.write( ".3 * x + .8 * y becomes .3 * 1.2 + .8 * 4.8 which becomes .36 + 3.84 which becomes 4.2\r
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\n" ); document.write( "\n" ); document.write( "4.2 / 6 = .7 = 70% which satisfies the requirements of the problem.\r
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\n" ); document.write( "\n" ); document.write( "1.2 liters of a 30% mixture added to 4.8 liters of an 80% mixture results in 6 liters of a 70% solution.\r
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