document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=309433>Question 309433</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I think I got the equation right to solve this word problem:  You drive to California.  On the way, you averaged 10 miles per hour less, and the drive took you 5 extra hours.  What was your average speed on thw\e way to California?\r<BR>\n" );
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document.write( "This is the formula I used but not sure how to solve it:<BR>\n" );
document.write( "1500=(R-10)(T+5) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #221309 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=221309\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> You drive to California. On the way, you averaged 10 miles per hour less, and the drive took you 5 extra hours. What was your average speed on the way to California? <BR>\n" );
document.write( "This is the formula I used but not sure how to solve it:<BR>\n" );
document.write( "1500=(R-10)(T+5)<BR>\n" );
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document.write( "From-California DATA:<BR>\n" );
document.write( "distance = 1500 miles ; rate = r mph ; time = t hrs<BR>\n" );
document.write( "Note: rt = 1500<BR>\n" );
document.write( "t = 1500/r <BR>\n" );
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document.write( "To-California DATA:<BR>\n" );
document.write( "distance = 1500 miles ; rate = r-10 mph ; time = t+5 hrs<BR>\n" );
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document.write( "Note: (r-10)(t+5) = 1500 <BR>\n" );
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document.write( "You have two equations; solve the system:<BR>\n" );
document.write( "rt-10t+5r-50 = 1500<BR>\n" );
document.write( "1500 -10(1500/r)+5r-50 = 1500<BR>\n" );
document.write( "-10(1500/r)+5r-50 = 0<BR>\n" );
document.write( "Multiply thru by r to get:<BR>\n" );
document.write( "-10(1500) + 5r^2 - 50r = 0<BR>\n" );
document.write( "Divide thru by 5 to get:<BR>\n" );
document.write( "-2(1500) + r^2 - 10r = 0<BR>\n" );
document.write( "r^2 -10r - 3000 = 0<BR>\n" );
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document.write( "r = [10 +- sqrt(100+4*3000)]/2<BR>\n" );
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document.write( "r = [10 +- sqrt(12100)]/2<BR>\n" );
document.write( "Positive solution:<BR>\n" );
document.write( "r = [120]/2<BR>\n" );
document.write( "r = 60 mph<BR>\n" );
document.write( "t = 1500/60 = 25 hrs.<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( "==================================<BR>\n" );
document.write( " </SPAN>\n" );
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