document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=279065>Question 279065</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Anita has two sisters and three brothers. The mean of all their ages is 6 years. What will their mean age be 10 years from now? Twenty years from now? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #202967 by </B><A HREF=/tutors/aboutme.mpl?userid=Mr.Gardner><B>Mr.Gardner(4)</B></A><img src=\"/images/stars/iconNewId_16x16.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Mr.Gardner><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=202967\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> This is how I answered the question. If you let the siblings be represented by the letters a,b,c,d,e,f (there are six of them including Anita), then you can set up the following equation:\r<BR>\n" );
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document.write( "(a+b+c+d+e+f)/6 = 6. \r<BR>\n" );
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document.write( "This comes from the formula for a mean. \r<BR>\n" );
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document.write( "In ten years, each sibling will have added 10 years to their age, so this is the equation for the mean of their ages ten years from now:\r<BR>\n" );
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document.write( "[(a+10)+(b+10)+(c+10)+(d+10)+(e+10)+(f+10)]/6\r<BR>\n" );
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document.write( "By adding all of the 10's in the numerator we get:\r<BR>\n" );
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document.write( "(60+a+b+c+d+e+f)/6\r<BR>\n" );
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document.write( "We can seperate this fraction into:\r<BR>\n" );
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document.write( "60/6 + (a+b+c+d+e+f)/6\r<BR>\n" );
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document.write( "60/6 = 10 and we know that (a+b+c+d+e+f)/6 = 6, so the answer is:\r<BR>\n" );
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document.write( "10+6 = 16.\r<BR>\n" );
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document.write( "So in ten years the mean age increased 10 years.\r<BR>\n" );
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document.write( "Using the same arithmetic we get that the mean age in 20 years will have increased 20 years, so the answer to the second question is 26. </SPAN>\n" );
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