document.write( "Question 254027: four pencils and five pens cost $2.00. Three pencils and four pens cost$1.58. Find the cost of a pencil and the cost of a pen \n" ); document.write( "

Algebra.Com's Answer #186362 by stanbon(75887) $\"\"$ $\"About$

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four pencils and five pens cost $2.00. Three pencils and four pens cost$1.58. Find the cost of a pencil and the cost of a pen
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\n" ); document.write( "Equations:
\n" ); document.write( "4n + 5p = 200
\n" ); document.write( "3n + 4p = 158
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\n" ); document.write( "Multiply thru the 1st equation by 3
\n" ); document.write( "Multiply thru the 2nd equation by 4
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\n" ); document.write( "12n + 15p = 3*200
\n" ); document.write( "12n + 16p = 4*158
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\n" ); document.write( "Subtract the 1st equation from the 2nd and solve for \"p\":
\n" ); document.write( "p = 4*158-3*200
\n" ); document.write( "p = 32 cents (cost of a pen)
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\n" ); document.write( "Substitute into 4n + 5p = 200 to solve for \"n\":
\n" ); document.write( "4n + 5*32 = 200
\n" ); document.write( "4n + 160 = 200
\n" ); document.write( "4n = 40
\n" ); document.write( "n = 10 cents (cost of a pencil)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "

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