document.write( "Question 191762: Hi, I'm kate and I need some help with linear systems.
\n" ); document.write( "Snookers Lumber can convert logs into either lumber or plywood. In a given day the mill turns out twice as many units of plywood as lumber. The mill makes a profit of $30 a unit of lumber and $45 on a unit of plywood. How many of each unit must be produced and sold in order to make a profit of $12480. Thank-you for your help.
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Algebra.Com's Answer #143870 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
Let x=# of plywood boards, y=# of lumber \r
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\n" ); document.write( "\n" ); document.write( "\"In a given day, the mill turns out twice as many units of plywood as lumber\" translates to \"x=2y\"\r
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\n" ); document.write( "\n" ); document.write( "\"It makes a profit of $30 on a unit of lumber and $45 on a unit of plywood. How many of each unit must be produced and sold in order to make a profit of $12480\" translates to: \"45x%2B30y=12480\"\r
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\n" ); document.write( "\n" ); document.write( "So we have the following system of equations\r
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\n" ); document.write( "\n" ); document.write( "\"x=2y\"
\n" ); document.write( "\"45x%2B30y=12480\"\r
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\n" ); document.write( "\n" ); document.write( "\"45%282y%29%2B30y=12480\" Plug in \"x=2y\" into the second equation. In other words, replace each \"x\" with \"2y\". Notice we've eliminated the \"x\" variables. So we now have a simple equation with one unknown.\r
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\n" ); document.write( "\n" ); document.write( "\"90y%2B30y=12480\" Distribute\r
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\n" ); document.write( "\n" ); document.write( "\"120y=12480\" Combine like terms on the left side\r
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\n" ); document.write( "\n" ); document.write( "\"y=%2812480%29%2F%28120%29\" Divide both sides by 120 to isolate y\r
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\n" ); document.write( "\n" ); document.write( "\"y=104\" Divide\r
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\n" ); document.write( "\n" ); document.write( "Now that we know that \"y=104\", we can plug this into \"x=2y\" to find \"x\"\r
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\n" ); document.write( "\n" ); document.write( "\"x=2%28104%29\" Substitute \"104\" for each \"y\"\r
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\n" ); document.write( "\n" ); document.write( "\"x=208\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "So our answers are \"x=208\" and \"y=104\" which the ordered pair \r
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\n" ); document.write( "\n" ); document.write( "This means that they must sell 208 units of plywood and 104 units of lumber to obtain a profit of $12,480
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