document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=157290>Question 157290</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/0130264857/algebrahomeworkh>Prentice Hall Algebra 1</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> two planes leave simultaneously from an airport, one flying east and the other west. they are 870 mi apart after 3/4 h. if the eastbound plane averages 120 mi/h more than the westbound plane, at what rate is each plane flying? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #115925 by </B><A HREF=/tutors/aboutme.mpl?userid=midwood_trail><B>midwood_trail(310)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=midwood_trail><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=115925\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Two planes leave simultaneously from an airport. One flying east and the other west. They are 870 miles apart after 3/4 hours. If the eastbound plane averages 120 miles an hour more than the westbound plane, at what rate is each plane flying?\r<BR>\n" );
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document.write( "Did you try making a table or chart?\r<BR>\n" );
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document.write( "What do we know?\r<BR>\n" );
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document.write( "They are going in OPPOSITE directions when miles apart is known.  This means times equal, total distance given.\r<BR>\n" );
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document.write( "We also know their time.\r<BR>\n" );
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document.write( "We need to find their speed.\r<BR>\n" );
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document.write( "Let EP = eastbound plane\r<BR>\n" );
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document.write( "Let WP = westbound plane\r<BR>\n" );
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document.write( "We set up a table.\r<BR>\n" );
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document.write( "..........time..........rate.............distance\r<BR>\n" );
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document.write( "EP........3/4..........x + 120........(3/4)(x + 120)\r<BR>\n" );
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document.write( "WP........3/4.............x............(3/4)(x)\r<BR>\n" );
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document.write( "From the table we make this equation:\r<BR>\n" );
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document.write( "(3/4)(x + 120) + (3/4)(x) = the total miles they are apart or 870 miles\r<BR>\n" );
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document.write( "We now do algebra.\r<BR>\n" );
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document.write( "(3/4)(x + 120) becomes (3x/4) + 90\r<BR>\n" );
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document.write( "(3/4)(x) can be written (3x/4)\r<BR>\n" );
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document.write( "We now have a fractional equation:\r<BR>\n" );
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document.write( "(3x/4) + 90 + (3x/4) = 870\r<BR>\n" );
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document.write( "Subtracting 90 from both sides we get this:\r<BR>\n" );
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document.write( "(3x/4) + (3x/4) = 780\r<BR>\n" );
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document.write( "Let's add the left side fractions.\r<BR>\n" );
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document.write( "It's just adding fractions just like you did back in elementary school.\r<BR>\n" );
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document.write( "6x/4 = 780....This is the equation I got after adding the fractions.\r<BR>\n" );
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document.write( "To remove the fraction on the left side, multiply both sides by 4.\r<BR>\n" );
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document.write( "We are left with:\r<BR>\n" );
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document.write( "6x = 3120\r<BR>\n" );
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document.write( "To find x, divide both sides by 6.\r<BR>\n" );
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document.write( "x = 3120/6\r<BR>\n" );
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document.write( "x = 520 miles per hour.\r<BR>\n" );
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document.write( "Do you see that all that work is just algebra?\r<BR>\n" );
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document.write( "Are we done?\r<BR>\n" );
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document.write( "No!  We found x but have not found their individual speed or RATE.\r<BR>\n" );
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document.write( "Eastbound plane travel at 120 mph more than the Westbound plane.\r<BR>\n" );
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document.write( "Here is your answer:\r<BR>\n" );
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document.write( "Eastbound plane = 120 + 520 or 640 miles per hour\r<BR>\n" );
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document.write( "Westbound plane is the value of x I found above or 520 miles per hour\r<BR>\n" );
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document.write( "Did you follow?\r<BR>\n" );
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document.write( " </SPAN>\n" );
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