document.write( "Question 1182899: A baker purchased 13 lb of wheat flour and 10 lb of rye flour for a total cost of $14.10. A second purchase, at the same prices, included 15 lb of wheat flour and 14 lb of rye flour. The cost of the second purchase was $17.50. Find the cost per pound of the wheat flour and of the rye flour. \n" ); document.write( "

Algebra.Com's Answer #813017 by ikleyn(52835) $\"\"$ $\"About$

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\n" ); document.write( "A baker purchased 13 lb of wheat flour and 10 lb of rye flour for a total cost of $14.10.
\n" ); document.write( "A second purchase, at the same prices, included 15 lb of wheat flour and 14 lb of rye flour.
\n" ); document.write( "The cost of the second purchase was $17.50.
\n" ); document.write( "Find the cost per pound of the wheat flour and of the rye flour.
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document.write( "Let  x  be the price per pound of the wheat and \r\n" );
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document.write( "let  y  be the price per pound of the rye flour.\r\n" );
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document.write( "Write the system of two equations as you read the problem\r\n" );
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document.write( "    13x + 10y = 14.10    (1)\r\n" );
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document.write( "    15x + 14y = 17.50    (2)\r\n" );
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document.write( "Use the determinant method to solve the system (the same as the Cramer's rule).\r\n" );
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document.write( "The determinant of the coefficient matrix is  D = 13*14 - 15*10 = 32.\r\n" );
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document.write( "The determinant to find the unknown x is      Dx = 14.10*14 - 17.50*10 = 22.4;\r\n" );
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document.write( "    so  x =  =  = 0.7  dollars.\r\n" );
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document.write( "The determinant to find the unknown y is      Dy = 13*17.50 - 15*14.10 = 16;\r\n" );
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document.write( "    so  y =  =  = 0.5  dollars.\r\n" );
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document.write( "ANSWER.  The prices are  $0.7  for pound of wheat and  $0.5 for pound of rye flour.\r\n" );
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\n" ); document.write( "\n" ); document.write( "On Cramer's rule for solving systems of 2 equations in 2 unknowns see the lessons\r
\n" ); document.write( "\n" ); document.write( "    - What is a matrix?,\r
\n" ); document.write( "\n" ); document.write( "    - Determinant of a 2x2-matrix,\r
\n" ); document.write( "\n" ); document.write( "    - HOW TO solve system of linear equations in two unknowns using determinant (Cramer's rule),\r
\n" ); document.write( "\n" ); document.write( "    - Solving systems of linear equations in two unknowns using the Cramer's rule,\r
\n" ); document.write( "\n" ); document.write( "    - Solving word problems by the Cramer's rule after reducing to systems of linear equations in two unknowns, \r
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\n" ); document.write( "\n" ); document.write( "Also, you have this free of charge online textbook in ALGEBRA-II in this site\r
\n" ); document.write( "\n" ); document.write( "    - ALGEBRA-II - YOUR ONLINE TEXTBOOK.\r
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\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this online textbook under the topic
\n" ); document.write( "     \"2x2-Matrices, determinants, Cramer's rule for systems in two unknowns\" \r
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