document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=86552>Question 86552</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Humans have about 1,400,000 hairs on their head and lose an average of 75 hairs each day.  If a person's body were to never replace a hair, approximately how many years would it take for a person to have 1000 hairs left on their head?  (Assume that a person can live significantly longer than the average life span.)<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #62593 by </B><A HREF=/tutors/aboutme.mpl?userid=bucky><B>bucky(2189)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=bucky><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=62593\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> On the average human head there are 1,400,000 hairs. If you take away 75 hairs every day<BR>\n" );
document.write( "in N days you will have taken away 75*N hairs. For example, in 10 days you would have<BR>\n" );
document.write( "taken away 75*10 or 750 hairs. <BR>\n" );
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document.write( "After N days the number of hairs you will have left (call it H) is 1,400,000 less the <BR>\n" );
document.write( "75*N hairs that have been lost.  In equation form this is:<BR>\n" );
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document.write( "H = 1,400,000 - 75*N<BR>\n" );
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document.write( "The problem tells you that H is to be 1,000. Substituting this into the equation results in:<BR>\n" );
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document.write( "1,000 = 1,400,000 - 75*N<BR>\n" );
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document.write( "Let's get the term containing N over to the left side of the equation. We can do that by<BR>\n" );
document.write( "adding 75*N to both sides.  This addition results in:<BR>\n" );
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document.write( "75*N + 1,000 = 1,400,000<BR>\n" );
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document.write( "Next, let's get the 1,000 on the left side moved over to the right side. Do this by subtracting<BR>\n" );
document.write( "1,000 from both sides. This subtraction of 1,000 from both sides reduces the equation to:<BR>\n" );
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document.write( "75*N = 1,399,000<BR>\n" );
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document.write( "Now we can solve for N by dividing both sides of the equation by 75 (the multiplier<BR>\n" );
document.write( "of N) to get:<BR>\n" );
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document.write( "N = 1,399,000/75 = 18,653<BR>\n" );
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document.write( "The actual answer is 18,653.3333 but I've rounded it off to a whole number of days.<BR>\n" );
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document.write( "Note that if you take 365 as the number of days in a year, this number of days is equal to:<BR>\n" );
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document.write( "18,653/365 = 51 years<BR>\n" );
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document.write( "Actually, it's about 51.10 years, but I've rounded this off to an even number of years also.<BR>\n" );
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document.write( "And the 1,000 hairs that are left will be gone (at the rate of 75 hairs lost per day) in:<BR>\n" );
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document.write( "N = 1,000/75 = 13.3 days.<BR>\n" );
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document.write( "So two weeks after you're down to 1,000 hairs you would be bald as a basketball.<BR>\n" );
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document.write( "Hope this helps you to understand the problem. </SPAN>\n" );
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