document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=697171>Question 697171</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The sum of a man's age and his sisters age is 91. The man is twice as old as his sister was when the man was as old as his sister is today. How old are they? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #429726 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><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=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=429726\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+ ALIGN=MIDDLE  ALT=\"+a+\"   DISABLED_style= \"max-width:90%; height:auto;\" >  = the Man's age now<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+ ALIGN=MIDDLE  ALT=\"+b+\"   DISABLED_style= \"max-width:90%; height:auto;\" >  = his Sister's age now<BR>\n" );
document.write( "given:<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+%2B+b+=+91+ ALIGN=MIDDLE  ALT=\"+a+%2B+b+=+91+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "When the Man's age was <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+ ALIGN=MIDDLE  ALT=\"+b+\"   DISABLED_style= \"max-width:90%; height:auto;\" > , the age his<BR>\n" );
document.write( "Sister is now, how old was his Sister then?<BR>\n" );
document.write( "--------------<BR>\n" );
document.write( "The separation in their ages will always be <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+-+b+ ALIGN=MIDDLE  ALT=\"+a+-+b+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "( assuming the Man is older )<BR>\n" );
document.write( "So, when the Man was  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+ ALIGN=MIDDLE  ALT=\"+b+\"   DISABLED_style= \"max-width:90%; height:auto;\" > years old, his Sister<BR>\n" );
document.write( "was <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+-+%28+a+-+b+%29+=+b+-+a+%2B+b+ ALIGN=MIDDLE  ALT=\"+b+-+%28+a+-+b+%29+=+b+-+a+%2B+b+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+2b+-+a+ ALIGN=MIDDLE  ALT=\"+2b+-+a+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "---------------------<BR>\n" );
document.write( "The man is now twice this age, so he is<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+2%2A%28+2b+-+a+%29+=+4b+-+2a+ ALIGN=MIDDLE  ALT=\"+2%2A%28+2b+-+a+%29+=+4b+-+2a+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "And, I can now say<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+=+4b+-+2a+ ALIGN=MIDDLE  ALT=\"+a+=+4b+-+2a+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+3a+=+4b+ ALIGN=MIDDLE  ALT=\"+3a+=+4b+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+=+%28+3%2F4%29%2Aa+ ALIGN=MIDDLE  ALT=\"+b+=+%28+3%2F4%29%2Aa+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Substitute this into (1)<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+%2B+b+=+91+ ALIGN=MIDDLE  ALT=\"+a+%2B+b+=+91+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+%2B+%283%2F4%29%2Aa+=+91+ ALIGN=MIDDLE  ALT=\"+a+%2B+%283%2F4%29%2Aa+=+91+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%287%2F4%29%2Aa+=+91+ ALIGN=MIDDLE  ALT=\"+%287%2F4%29%2Aa+=+91+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+=+%284%2F7%29%2A91+ ALIGN=MIDDLE  ALT=\"+a+=+%284%2F7%29%2A91+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+=+52+ ALIGN=MIDDLE  ALT=\"+a+=+52+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "and, since<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+%2B+b+=+91+ ALIGN=MIDDLE  ALT=\"+a+%2B+b+=+91+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+52+%2B+b+=+91+ ALIGN=MIDDLE  ALT=\"+52+%2B+b+=+91+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+=+91+-+52+ ALIGN=MIDDLE  ALT=\"+b+=+91+-+52+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+=+39+ ALIGN=MIDDLE  ALT=\"+b+=+39+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The man is 52<BR>\n" );
document.write( "His Sister is 39<BR>\n" );
document.write( "---------<BR>\n" );
document.write( "check:<BR>\n" );
document.write( "52 - 39 = 13, which is always<BR>\n" );
document.write( "the difference in their ages<BR>\n" );
document.write( "When the man was 39 , his Sister was 39 - 13 = 26 <BR>\n" );
document.write( "The Man is twice this age, or 2*26 = 52<BR>\n" );
document.write( "OK<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );