document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1059463>Question 1059463</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The sum of the ages of Mark's two sons is equal to his own age of 51. <BR>\n" );
document.write( "21 years ago, Mark's older son was twice as old as the younger son. <BR>\n" );
document.write( "How old was Mark when the sum of his sons' ages was half his age? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #674512 by </B><A HREF=/tutors/aboutme.mpl?userid=jorel555><B>jorel555(1290)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jorel555><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=674512\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let Mark's older son be m, and his younger son be n. Then<BR>\n" );
document.write( "m+n=51<BR>\n" );
document.write( "m=51-n<BR>\n" );
document.write( "and<BR>\n" );
document.write( "m-21=2(n-21), So:<BR>\n" );
document.write( "51-n-21=2n-42<BR>\n" );
document.write( "3n=72<BR>\n" );
document.write( "n=24<BR>\n" );
document.write( "Let p be the number of years ago that m and n together made half his age. Then<BR>\n" );
document.write( "51-p=2(24-p+27-p)<BR>\n" );
document.write( "51-p=48+54-4p<BR>\n" );
document.write( "3p=51<BR>\n" );
document.write( "p=17<BR>\n" );
document.write( "17 years ago, Mark was twice as old as his sons combined. &#9786;&#9786;&#9786;&#9786;<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );