document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1184064>Question 1184064</A>: <I><SPAN STYLE=\"word-break: break-all;\"> During one month, a homeowner used 700 units of electricity and 100 units of gas for a total cost of $486. The next month, 500 units of electricity and 250 units of gas were used for a total cost of $415. Find the cost per unit of gas.<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #849883 by </B><A HREF=/tutors/aboutme.mpl?userid=CPhill><B>CPhill(1959)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=CPhill><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=CPhill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=849883\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Here's how to solve this problem:\r<BR>\n" );
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document.write( "**Let:**\r<BR>\n" );
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document.write( "* 'e' be the cost per unit of electricity.<BR>\n" );
document.write( "* 'g' be the cost per unit of gas.\r<BR>\n" );
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document.write( "**Set up the equations:**\r<BR>\n" );
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document.write( "* **Equation 1 (Month 1):** 700e + 100g = 486<BR>\n" );
document.write( "* **Equation 2 (Month 2):** 500e + 250g = 415\r<BR>\n" );
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document.write( "**Solve the equations:**\r<BR>\n" );
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document.write( "One way to solve this is using elimination:\r<BR>\n" );
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document.write( "1. **Multiply Equation 1 by 2.5:**<BR>\n" );
document.write( "   1750e + 250g = 1215\r<BR>\n" );
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document.write( "2. **Subtract Equation 2 from the modified Equation 1:**<BR>\n" );
document.write( "   (1750e + 250g) - (500e + 250g) = 1215 - 415<BR>\n" );
document.write( "   1250e = 800\r<BR>\n" );
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document.write( "3. **Solve for e:**<BR>\n" );
document.write( "   e = 800 / 1250<BR>\n" );
document.write( "   e = 0.64\r<BR>\n" );
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document.write( "4. **Substitute the value of e back into either Equation 1 or 2 to solve for g. Let's use Equation 1:**<BR>\n" );
document.write( "   700(0.64) + 100g = 486<BR>\n" );
document.write( "   448 + 100g = 486<BR>\n" );
document.write( "   100g = 38<BR>\n" );
document.write( "   g = 0.38\r<BR>\n" );
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document.write( "**Answer:**\r<BR>\n" );
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document.write( "The cost per unit of gas is $0.38.<BR>\n" );
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