document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=635990>Question 635990</A>: <I><SPAN STYLE=\"word-break: break-all;\"> my current age is 4 times what my sisters age was 20 years ago. i am now twice as old as i was 20 years ago. ten years ago, my sisters age was 1/2 of my current age. ten years ago, my age was 1.5 times my sisters age. what are our current ages? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #400747 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=400747\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let y = your current age<BR>\n" );
document.write( "Let s = sister's current age<BR>\n" );
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document.write( "Write an equation for each statement, simplify as much as possible:<BR>\n" );
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document.write( "\"my current age is 4 times what my sisters age was 20 years ago.\"<BR>\n" );
document.write( "y = 4(s-20)<BR>\n" );
document.write( "y = 4s - 80<BR>\n" );
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document.write( "\" I am now twice as old as i was 20 years ago.\"<BR>\n" );
document.write( "y = 2(y-20)<BR>\n" );
document.write( "y = 2y - 40<BR>\n" );
document.write( "40 = 2y -y<BR>\n" );
document.write( "y = 40 yr, your present age<BR>\n" );
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document.write( "Right here you know enough to solve this<BR>\n" );
document.write( "40 = 4s - 80<BR>\n" );
document.write( "40 + 80 = 4s<BR>\n" );
document.write( "s = 120/4<BR>\n" );
document.write( "s = 30 is the sisters age<BR>\n" );
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document.write( "You can check this using the rest of the equations with y=40, s=30<BR>\n" );
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document.write( "ten years ago, my sisters age was 1/2 of my current age. \"<BR>\n" );
document.write( "s - 10 = .5y<BR>\n" );
document.write( "multiply both sides by 2<BR>\n" );
document.write( "2(s-10) = y<BR>\n" );
document.write( "2s - 20 = y<BR>\n" );
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document.write( "\"ten years ago, my age was 1.5 times my sisters age.\"<BR>\n" );
document.write( "y - 10 = 1.5(s-10)<BR>\n" );
document.write( "y - 10 = 1.5s - 15<BR>\n" );
document.write( "y = 1.5s - 15 + 10<BR>\n" );
document.write( "y = 1.5s - 5<BR>\n" );
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document.write( "Two unknowns, two equations are sufficient.\r<BR>\n" );
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