document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=69814>Question 69814</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I never seem to be able to set up equations from story problems.  I think I have an idea about how to do it, then am usually disappointed.  If I see an example, I can usually apply it to similar problems, but I rarely remember how they work for long.<BR>\n" );
document.write( "Example:<BR>\n" );
document.write( "The launch site for Trigon Balloon Co. is 250ft. above sea level.  A hot-air balloon is launched from the site and begins to rise at a rate of 110ft/min.  At the same time, another balloon, 2220 ft. above sea level begins to descend at a rate of 150 ft/min.<BR>\n" );
document.write( "How long will it be until the balloons are at the same elevation?<BR>\n" );
document.write( "What will their elevation be then?\r<BR>\n" );
document.write( "\n" );
document.write( "I set it up this way, but it doesn't work out<BR>\n" );
document.write( "250 + 110x = 2220 - 150x </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #49755 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=49755\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The launch site for Trigon Balloon Co. is 250ft. above sea level. A hot-air balloon is launched from the site and begins to rise at a rate of 110ft/min. At the same time, another balloon, 2220 ft. above sea level begins to descend at a rate of 150 ft/min<BR>\n" );
document.write( ":.<BR>\n" );
document.write( "How long will it be until the balloons are at the same elevation?<BR>\n" );
document.write( "What will their elevation be then?<BR>\n" );
document.write( ":<BR>\n" );
document.write( "I set it up this way, but it doesn't work out<BR>\n" );
document.write( ":<BR>\n" );
document.write( "It looks OK to me, it has to work:<BR>\n" );
document.write( ":<BR>\n" );
document.write( "250 + 110x = 2220 - 150x<BR>\n" );
document.write( "110x + 150x = 2220 - 250<BR>\n" );
document.write( "260x = 1970<BR>\n" );
document.write( "x = 1970/260<BR>\n" );
document.write( "x = 7.6 min or 7 min 36 sec<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Check by finding how many feet it will travel at a combined speed:<BR>\n" );
document.write( "7.6(110+150) = 1976 ~ 1970 (we rounded off 7.5796 to 7.6)<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );