document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=572769>Question 572769</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Sally is 40 years older than her son Peter. In 5 years she will be twice his age. How old are Sally and Peter? Make two solutions, one using a variable for Sally and one for Peter. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #368818 by </B><A HREF=/tutors/aboutme.mpl?userid=mathsmiles><B>mathsmiles(68)</B></A><img src=\"/images/stars/stars-08.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mathsmiles><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=mathsmiles><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=368818\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> I understand everything except the last sentence.  I'm going to proceed anyway and hope this helps you.\r<BR>\n" );
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document.write( "Sally's age now = S<BR>\n" );
document.write( "Peter's age now = P\r<BR>\n" );
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document.write( "Sally's age 5 years from now = S + 5<BR>\n" );
document.write( "Peter's age 5 years from now = P + 5\r<BR>\n" );
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document.write( "We also know a few facts:<BR>\n" );
document.write( "S = P + 40  Sally is 40 years older than Peter<BR>\n" );
document.write( "(S+5) = 2(P+5)\r<BR>\n" );
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document.write( "Let's use the first equation to substitute for Sally's age (S) in the second equation:<BR>\n" );
document.write( "((P+40) + 5) = 2(P+5) Since the left side is all addition, we can remove the parens without a problem:<BR>\n" );
document.write( "P + 40 + 5 = 2(P + 5)<BR>\n" );
document.write( "P + 45 = 2(P + 5)  Now multiply out the paren on the right:<BR>\n" );
document.write( "P + 45 = 2P + 10  Subtract P from both sides:<BR>\n" );
document.write( "45 = P + 10   Subtract 10 from both sides:<BR>\n" );
document.write( "35 = P\r<BR>\n" );
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document.write( "Peter is 35.  Since Sally is 40 years older than Peter, she is 75.\r<BR>\n" );
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document.write( "Checking our answer:<BR>\n" );
document.write( "In 5 years, she'll be twice his age:<BR>\n" );
document.write( "Peter will be 35 + 5 = 40 in 5 years.  <BR>\n" );
document.write( "Sally will be 75 + 5 = 80 in 5 years<BR>\n" );
document.write( "Sally will be twice Peter's age.  Correct!<BR>\n" );
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