document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=2325>Question 2325</A>: <I><SPAN STYLE=\"word-break: break-all;\"> \"Grandpa how old are you?\"Billy asked. His grndfather retorted,\"why,the average age of you grandmother and me is seventy years,Billy.\" \"But how old are you_?\" he asked again,seemiing impatient.<BR>\n" );
document.write( "\"Well,let me put it another way: I am twice as old as your grandmother was when I was her present age.Perhaps you can figure out both our ages by using some of that algebra you learned today.\" Scratching his head,Billy went to his room. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #958 by </B><A HREF=/tutors/aboutme.mpl?userid=longjonsilver><B>longjonsilver(2297)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=longjonsilver><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=longjonsilver><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=958\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> define:\r<BR>\n" );
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document.write( "x = grandpa's age now<BR>\n" );
document.write( "y = grandma's age now.\r<BR>\n" );
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document.write( "1. <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28x%2By%29%2F2+=+70 ALIGN=MIDDLE  ALT=\"%28x%2By%29%2F2+=+70\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%2By=140 ALIGN=MIDDLE  ALT=\"x%2By=140\"   DISABLED_style= \"max-width:90%; height:auto;\" >--eqn1\r<BR>\n" );
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document.write( "2. when he was her age: he was y, she was y-(x-y) where (x-y) is the difference in their ages. Use numbers to check this..just make some up and look at how you would work it out with numbers.\r<BR>\n" );
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document.write( "x = 2(y-(x-y)) --eqn2. this is a tricky one to get.\r<BR>\n" );
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document.write( "Re-arranging gives...\r<BR>\n" );
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document.write( "x = 2(2y-x)<BR>\n" );
document.write( "x = 4y - 2x<BR>\n" );
document.write( "3x = 4y --eqn3\r<BR>\n" );
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document.write( "sub 1 into 3 for x, gives\r<BR>\n" );
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document.write( "3(140-y) = 4y<BR>\n" );
document.write( "420-3y= 4y<BR>\n" );
document.write( "7y=420<BR>\n" );
document.write( "y=60\r<BR>\n" );
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document.write( "so x=80\r<BR>\n" );
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document.write( "check...grandma was 40 when he was her age now, 60. And Grandpa's current age of 80 is twice that..so correct.\r<BR>\n" );
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document.write( "jon. </SPAN>\n" );
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