document.write( "Question 162692: Two airplanes leave Dallas at the same time and fly in opposite directions. One airplane travels at 80 miles per hour faster. After 3 hours they are 2940 miles apart. What is the speed of each airplane? \n" ); document.write( "
Algebra.Com's Answer #119927 by nerdybill(7384)\"\" \"About 
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Two airplanes leave Dallas at the same time and fly in opposite directions. One airplane travels at 80 miles per hour faster. After 3 hours they are 2940 miles apart. What is the speed of each airplane?
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\n" ); document.write( "You will be applying the \"distance formula\":
\n" ); document.write( "d = rt
\n" ); document.write( "where
\n" ); document.write( "d is distance
\n" ); document.write( "r is rate or speed
\n" ); document.write( "t is time
\n" ); document.write( ".
\n" ); document.write( "Let x = speed of one plane
\n" ); document.write( "then because \"One airplane travels at 80 miles per hour faster\"
\n" ); document.write( "x+80 = speed of the other plane
\n" ); document.write( ".
\n" ); document.write( "\"distance traveled by 1st plane\" + \"distance traveled by 2nd\" = \"distance apart\"
\n" ); document.write( "3x + 3(x+80) = 2940
\n" ); document.write( "dividing both sides by 3:
\n" ); document.write( "x + (x+80) = 980
\n" ); document.write( "2x + 80 = 980
\n" ); document.write( "2x = 900
\n" ); document.write( "x = 450 mph (one plane)
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\n" ); document.write( "2nd plane:
\n" ); document.write( "x+80 = 450+80 = 530 mph (2nd plane)
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