document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=280051>Question 280051</A>: <I><SPAN STYLE=\"word-break: break-all;\"> From an original group of boys and girls, twenty girls leave. There are then left two boys for each girl. After this, sixty boys leave. There are then two girls for each boy.The number of girls in the original group was:\r<BR>\n" );
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document.write( "(A) 81 (B) 72 (C) 68 (D) 60 (E) 50 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #203587 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=203587\">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=g ALIGN=MIDDLE  ALT=\"g\"   DISABLED_style= \"max-width:90%; height:auto;\" > = original number of girls<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;\" > = original number of boys<BR>\n" );
document.write( "given:<BR>\n" );
document.write( "Initially, there are:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=b+%2B+g ALIGN=MIDDLE  ALT=\"b+%2B+g\"   DISABLED_style= \"max-width:90%; height:auto;\" > in the group<BR>\n" );
document.write( "20 girls leave<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=b+%2B+%28g+-+20%29 ALIGN=MIDDLE  ALT=\"b+%2B+%28g+-+20%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > in the group<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=b+=+2%2A%28g+-+20%29 ALIGN=MIDDLE  ALT=\"b+=+2%2A%28g+-+20%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Then <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=60 ALIGN=MIDDLE  ALT=\"60\"   DISABLED_style= \"max-width:90%; height:auto;\" > boys leave<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28b+-+60%29+%2B+%28g+-+20%29 ALIGN=MIDDLE  ALT=\"%28b+-+60%29+%2B+%28g+-+20%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > in the group<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=g+-+20+=+2%2A%28b+-+60%29 ALIGN=MIDDLE  ALT=\"g+-+20+=+2%2A%28b+-+60%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) and (2) are 2 equations with 2 unknowns, so<BR>\n" );
document.write( "it's solvable<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=b+=+2%2A%28g+-+20%29 ALIGN=MIDDLE  ALT=\"b+=+2%2A%28g+-+20%29\"   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+=+2g+-+40 ALIGN=MIDDLE  ALT=\"b+=+2g+-+40\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2g+-+b+=+40 ALIGN=MIDDLE  ALT=\"2g+-+b+=+40\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=g+-+20+=+2%2A%28b+-+60%29 ALIGN=MIDDLE  ALT=\"g+-+20+=+2%2A%28b+-+60%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=g+-+20+=+2b+-+120 ALIGN=MIDDLE  ALT=\"g+-+20+=+2b+-+120\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-g+%2B+2b+=+100 ALIGN=MIDDLE  ALT=\"-g+%2B+2b+=+100\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Multiply both sides of (1) by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2 ALIGN=MIDDLE  ALT=\"2\"   DISABLED_style= \"max-width:90%; height:auto;\" > and add equations<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=4g+-+2b+=+80 ALIGN=MIDDLE  ALT=\"4g+-+2b+=+80\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-g+%2B+2b+=+100 ALIGN=MIDDLE  ALT=\"-g+%2B+2b+=+100\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3g+=+180 ALIGN=MIDDLE  ALT=\"3g+=+180\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=g+=+60 ALIGN=MIDDLE  ALT=\"g+=+60\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The number of girls in the original group was 60<BR>\n" );
document.write( "check answer:<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=b+=+2%2A%28g+-+20%29 ALIGN=MIDDLE  ALT=\"b+=+2%2A%28g+-+20%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=b+=+2%2A%2860+-+20%29 ALIGN=MIDDLE  ALT=\"b+=+2%2A%2860+-+20%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=b+=+80 ALIGN=MIDDLE  ALT=\"b+=+80\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=g+-+20+=+2%2A%28b+-+60%29 ALIGN=MIDDLE  ALT=\"g+-+20+=+2%2A%28b+-+60%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=60+-+20+=+2%2A%2880+-+60%29 ALIGN=MIDDLE  ALT=\"60+-+20+=+2%2A%2880+-+60%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=40+=+2%2A20 ALIGN=MIDDLE  ALT=\"40+=+2%2A20\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=40+=+40 ALIGN=MIDDLE  ALT=\"40+=+40\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "OK </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );