document.write( "Question 366839: When Ace Airlines changed to planes that flew 100 km/h faster than its old ones, the time of its 2800 km Dallas-Seattle flight was reduced by 30 min. Find the speed of the new planes. \n" ); document.write( "
Algebra.Com's Answer #261684 by mananth(16946)\"\" \"About 
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When Ace Airlines changed to planes that flew 100 km/h faster than its old ones, the time of its 2800 km Dallas-Seattle flight was reduced by 30 min. Find the speed of the new planes.
\n" ); document.write( "speed of 0ld plane be x
\n" ); document.write( "..
\n" ); document.write( "old plane time to seattle = 2800/x
\n" ); document.write( "new plane time to seattle = 2800/(x+100)
\n" ); document.write( "time reduction 1/2 hour
\n" ); document.write( "...
\n" ); document.write( "2800/x - 2800/(x+100)= 1/2
\n" ); document.write( "2800(x+100)-2800x/(x(x+100)= 1/2
\n" ); document.write( "2800x+280000-2800x= 1/2*(x*(x+100))
\n" ); document.write( "280000=1/2(x^2+100)
\n" ); document.write( "560000= x^2+100
\n" ); document.write( "x^2= 560000-100
\n" ); document.write( "x^2=559900
\n" ); document.write( "squareroot
\n" ); document.write( "x= 748.2 km/h
\n" ); document.write( "new plane speed = 748+100 = 848 km/h.\r
\n" ); document.write( "\n" ); document.write( "m.ananth@hotmail.ca \n" ); document.write( "
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