document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=94101>Question 94101</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/013062568x/algebrahomeworkh>prentice hall mathematics algebra 2</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> Two planes left an airport at noon. One flew east at a certain speed and the other flew west at twice the speed. The planes were 2700 mi apart in 3 h. How fast was each plane flying?<BR>\n" );
document.write( "                      ---THANKS FOR ALL YOUR HELP!!!!!!--- </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #68526 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=68526\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> To solve this problem use the distance formula that says the distance traveled is equal to <BR>\n" );
document.write( "speed times the time.<BR>\n" );
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document.write( "[Think of a car. If you go at 60 miles per hour times 2 hours, how many miles do you go???<BR>\n" );
document.write( "Pretty easy to see that the answer is 120 miles which comes from 60 times 2 hrs.]<BR>\n" );
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document.write( "Call the speed of one plane S. And since the other plane is going twice as fast, its speed is 2S.<BR>\n" );
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document.write( "Each plane flies for 3 hours.<BR>\n" );
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document.write( "The distance the first plane goes in 3 hours is its speed S times 3 hours which means it covers<BR>\n" );
document.write( "a distance of 3S.<BR>\n" );
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document.write( "The distance the second plane goes in 3 hours is its speed 2S times 3 hours which means<BR>\n" );
document.write( "it covers a distance of 6S.<BR>\n" );
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document.write( "The total distance that  the planes cover is the sum of these two distances, 3S and 6S<BR>\n" );
document.write( "and this equals 9S<BR>\n" );
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document.write( "But the problem says the total distance between the two planes is 2700 miles.<BR>\n" );
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document.write( "So we can write the equation:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=9S+=+2700 ALIGN=MIDDLE  ALT=\"9S+=+2700\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "Then solve for S by dividing both sides of this equation by 9 to get:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=S+=+2700%2F9+=+300 ALIGN=MIDDLE  ALT=\"S+=+2700%2F9+=+300\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "So one plane is going 300 miles per hour and the second plane, going twice as fast is<BR>\n" );
document.write( "going 600 miles per hour.<BR>\n" );
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document.write( "In 3 hours the first plane goes 300*3 = 900 miles. And in the same 3 hours the second plane<BR>\n" );
document.write( "goes 600*3 = 1800 miles. This makes the total distance between the (because they are going<BR>\n" );
document.write( "in opposite directions) 900 + 1800 = 2700 miles, just as the problem said it would be.<BR>\n" );
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document.write( "So the answer checks out ... 300 mph and 600 mph.<BR>\n" );
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document.write( "Hope this helps you see your way through the problem.<BR>\n" );
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