document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=22774>Question 22774</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I am a parent trying to help my son figure out how to solve the following:\r<BR>\n" );
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document.write( "Bill is twice as old as his brother Dan.  In 7 years Bill will be only one and one half as old as Dan.  How old is Bill now? \r<BR>\n" );
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document.write( "I would like the details on solving so I can teach him properly.\r<BR>\n" );
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document.write( "Thank you.\r<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 #11140 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=11140\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> First define the things you are asked for:\r<BR>\n" );
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document.write( "Let Bill be x years NOW<BR>\n" );
document.write( "Let Dan be y years NOW.\r<BR>\n" );
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document.write( "so, we know x = 2y --eqn1\r<BR>\n" );
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document.write( "Also, in 7 years time, Bill will be x+7 and Dan will be y+7. At this point, (x+7) = (3/2)(y+7) --eqn2\r<BR>\n" );
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document.write( "eqn2 simplifies to 2x+14 = 3y+21<BR>\n" );
document.write( "--> 2x - 3y = 7\r<BR>\n" );
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document.write( "Now, from eqn1, x = 2y, so sub this into the above version of eqn2, which becomes: 2(2y) - 3y = 7, which becomes\r<BR>\n" );
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document.write( "4y - 3y = 7<BR>\n" );
document.write( "y = 7\r<BR>\n" );
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document.write( "Hence x=2(7) --> x=14\r<BR>\n" );
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document.write( "So, Bill is 14 years old now.\r<BR>\n" );
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document.write( "check:<BR>\n" );
document.write( "in 7 years, we have ages 14 and 21, where 21 is \"one and one-half\" as much as 14.\r<BR>\n" );
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document.write( "Hope this is clear.\r<BR>\n" );
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document.write( "jon.<BR>\n" );
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