document.write( "Question 792516: A pilot flies a distance of 600 km. He could fly the same
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document.write( "distance in 30 minutes less time by increasing his average speed by
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document.write( "40 km/hr. Find his actual average speed. \n" );
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Algebra.Com's Answer #480035 by Alan3354(69443)![]() ![]() You can put this solution on YOUR website! A pilot flies a distance of 600 km. He could fly the same \n" ); document.write( "distance in 30 minutes less time by increasing his average speed by \n" ); document.write( "40 km/hr. Find his actual average speed. \n" ); document.write( "----------------- \n" ); document.write( "r = lower speed \n" ); document.write( "r*t = 600 --> t = 600/r \n" ); document.write( "(r+40)*(t-0.5) = 600 \n" ); document.write( "----- \n" ); document.write( "Sub for t in the 2nd eqn \n" ); document.write( "(r+40)*(600/r - 0.5) = 600 \n" ); document.write( "600 - 0.5r + 24000/r - 20 = 600 \n" ); document.write( "-0.5r + 24000/r = 20 \n" ); document.write( "-r + 48000/r = 40 \n" ); document.write( "r^2 - 48000 + 40r = 0 \n" ); document.write( "
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