document.write( "Question 144430: Flying against the jetstream, a jet travels 5250km in 7 hours. Flying with the jetstream, the same jet travels 4920km in 4 hours. What is the speed of the jet in still air, and what is the speed of the jetstream?
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Algebra.Com's Answer #105180 by ankor@dixie-net.com(22740)\"\" \"About 
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Flying against the jetstream, a jet travels 5250km in 7 hours. Flying with the jetstream, the same jet travels 4920km in 4 hours. What is the speed of the jet in still air, and what is the speed of the jetstream?
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\n" ); document.write( "Let s = jet's speed in still air:
\n" ); document.write( "Let w = jet-stream's speed
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\n" ); document.write( "Two dist equations
\n" ); document.write( "7(s-w) = 5250
\n" ); document.write( "4(s+w) = 4920
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\n" ); document.write( "Simplify both equation: divide the 1st eq by 7, divide the 2nd eq by 4, results:
\n" ); document.write( "s - w = 750
\n" ); document.write( "s + w = 1230
\n" ); document.write( "--------------adding eliminates w, find s
\n" ); document.write( "2s +0 = 1980
\n" ); document.write( "s = \"1980%2F2\"
\n" ); document.write( "s = 990 km/hr speed in still air
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\n" ); document.write( "Find w
\n" ); document.write( "s + w = 1230
\n" ); document.write( "990 +w =1230
\n" ); document.write( "w = 1230 - 990
\n" ); document.write( "w = 240 km/hr
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\n" ); document.write( "Check solutions:
\n" ); document.write( "7(990-240) = 5250 \n" ); document.write( "
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