document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1156484>Question 1156484</A>: <I><SPAN STYLE=\"word-break: break-all;\"> David and John's ages add up to twenty nine. Seven years ago David was twice the   <BR>\n" );
document.write( "age john. What are their present ages.<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 #779191 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13200)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=779191\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "You should know how to set up and solve the problem using formal algebra, as shown by the other tutor.<br><BR>\n" );
document.write( "But solving a problem like this using logical reasoning and mental arithmetic is also good brain exercise.<br><BR>\n" );
document.write( "If the sum of their ages is now 29, then 7 years ago the sum of their ages was 29-(2*7) = 29-14 = 15.<br><BR>\n" );
document.write( "If 7 years ago David was twice the age of John, then with their two ages adding to 15 David was 10 and John was 5.<br><BR>\n" );
document.write( "That was 7 years ago; so now their ages are 17 and 12.<br><BR>\n" );
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