document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=121815>Question 121815</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Sally bought three chocolate bars and a pack of gum and paid $1.75. Jake bought two chocolate bars and four packs of gum and paid $2.00. What's the cost of a chocolate bar and a pack of gum?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #89429 by </B><A HREF=/tutors/aboutme.mpl?userid=solver91311><B>solver91311(24713)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=solver91311><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=solver91311><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=89429\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let's say that a chocolate bar costs 'c' cents, and a pack of gum costs 'g' cents.\r<BR>\n" );
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document.write( "Sally bought 3 chocolate bars, so she spent 3c cents on chocolate.  Likewise, she spent 1g, or just g, cents on gum.  Together she spent $1.75, or 175 cents.  Now we can write:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3c%2Bg=175 ALIGN=MIDDLE  ALT=\"3c%2Bg=175\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "A similar analysis gives us an expression for Jake's purchase:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2c%2B4g=200 ALIGN=MIDDLE  ALT=\"2c%2B4g=200\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Now we have a system of two linear equations in two variables.  We are interested in determining the ordered pair (c,g) that satisfies both equations.  This looks like a good candidate for the elimination method because the substitution expressions look a little messy to me.  (This is a matter of personal preference, or perhaps the instructions in an assignment.  Either way, properly performed gets you to the same place)\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3c%2Bg=175 ALIGN=MIDDLE  ALT=\"3c%2Bg=175\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2c%2B4g=200 ALIGN=MIDDLE  ALT=\"2c%2B4g=200\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Multiply equation 1 by -4:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-12c%2B%28-4%29g=-700 ALIGN=MIDDLE  ALT=\"-12c%2B%28-4%29g=-700\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Add the result to the second equation:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-10c%2B0g=-500 ALIGN=MIDDLE  ALT=\"-10c%2B0g=-500\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Divide by -10<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=c=50 ALIGN=MIDDLE  ALT=\"c=50\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Now we know that chocolate bars cost 50 cents.  Substitute this value into either original equation:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3%2850%29%2Bg=175 ALIGN=MIDDLE  ALT=\"3%2850%29%2Bg=175\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=150%2Bg=175 ALIGN=MIDDLE  ALT=\"150%2Bg=175\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=g=175-150=25 ALIGN=MIDDLE  ALT=\"g=175-150=25\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "So gum costs 25 cents.\r<BR>\n" );
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document.write( "Finally, convert your answers back to dollars and cents notation because that was the form of the given values for money in this problem,\r<BR>\n" );
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document.write( "Chocolate Bars:  $0.50<BR>\n" );
document.write( "Gum: $0.25\r<BR>\n" );
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document.write( "Check the answer:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3%2850%29%2B25=150%2B25=175 ALIGN=MIDDLE  ALT=\"3%2850%29%2B25=150%2B25=175\"   DISABLED_style= \"max-width:90%; height:auto;\" > and<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2%2850%29%2B4%2825%29=100+%2B+100+=+200 ALIGN=MIDDLE  ALT=\"2%2850%29%2B4%2825%29=100+%2B+100+=+200\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( " </SPAN>\n" );
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