document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=783400>Question 783400</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I have slept on a waterbed since the 70's. Last year I had to replace the mattress. The waterbed mattress measures 80 inches by 84 inches by 10 inches tall. I filled the matress to capacity with water that I thought was about 92 degrees, but after the bed was filled I found out that the actual temperature was only 74 degrees. It took 3 days for the waterbed heater to warm it up to 92 degrees. I had to sleep on the couch for 3 nights. \r<BR>\n" );
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document.write( "One thing that I could have done was drain out part of the water and replace it with 140 degree water. If I had done this, how many gallons of the \"colder\" water would I have had to drain out of the bed and replace with the 140 degree water, so that the temperature of the bed would have been 92 degrees? \r<BR>\n" );
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document.write( "Note: 231 Cubic Inches = 1 Gallon \r<BR>\n" );
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document.write( "Soooooo confused on this question. Any help understanding would be great, thank you! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #476771 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=476771\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let x = amt of 74 degree water to be drain & amt of 140 degree water to be added<BR>\n" );
document.write( "Find the no. of gallons total<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%2880%2A84%2A10%29%2F231 ALIGN=MIDDLE  ALT=\"%2880%2A84%2A10%29%2F231\"   DISABLED_style= \"max-width:90%; height:auto;\" > ~ 290 gallons<BR>\n" );
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document.write( "74(290-x) + 140x = 92(290)<BR>\n" );
document.write( "21460 - 74x + 140x = 26680<BR>\n" );
document.write( "-74x + 140x = 26680 - 21460<BR>\n" );
document.write( "66x = 5220<BR>\n" );
document.write( "x = 5220/66<BR>\n" );
document.write( "x ~ 79 gallons<BR>\n" );
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document.write( "Drain 79 gallons of the 74 degree water out<BR>\n" );
document.write( "Add 79 gallons of the 140 degree water<BR>\n" );
document.write( "Should result in 92 degree water </SPAN>\n" );
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