document.write( "Question 150076: Two planes leave O'Hare Airport Chicago at the came time. One flies directly east at 540 miles per hour. the other flies directly west at 720 miles per hour. How long will it take them to be 1890 miles apart? \n" ); document.write( "
Algebra.Com's Answer #110167 by nerdybill(7384)\"\" \"About 
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Two planes leave O'Hare Airport Chicago at the came time. One flies directly east at 540 miles per hour. the other flies directly west at 720 miles per hour. How long will it take them to be 1890 miles apart?
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\n" ); document.write( "Here, you are expected to know the relationship:
\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 T = time flown in hours
\n" ); document.write( "then
\n" ); document.write( "\"distance traveled by eastbound plane\" = 540T
\n" ); document.write( "\"distance traveled by westbound plane\" = 720T
\n" ); document.write( ".
\n" ); document.write( "\"distance traveled by eastbound plane\" + \"distance traveled by westbound plane\" = \"distance apart\"
\n" ); document.write( "OR, we have:
\n" ); document.write( "540T + 720T = 1890
\n" ); document.write( "1260T = 1890
\n" ); document.write( "T = 1890/1260
\n" ); document.write( "T = 1.5 hours
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