document.write( "Question 1123584: a plane travels 390 miles in 2 hours traveling with the wind, going against the wind, the plane travels 330 mile in the same time. find the speed of the plane in still air and the speed of the wind. \n" ); document.write( "
Algebra.Com's Answer #739934 by josmiceli(19441)\"\" \"About 
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Let \"w\" = the speed of the wind
\n" ); document.write( "Let \"s\" = the speed of the plane in still air
\n" ); document.write( "——————-
\n" ); document.write( "Flying with the wind
\n" ); document.write( "(1) \"+390+=+%28+s%2Bw+%29%2A2+\"
\n" ); document.write( "Flying against the wind:
\n" ); document.write( "(2) \"+330+=+%28s-+w+%29%2A2+\"
\n" ); document.write( "—————————————
\n" ); document.write( "(1) \"+195+=+s+%2B+w+\"
\n" ); document.write( "(2) \"+165+=+s+-+w+\"
\n" ); document.write( "Add the equations
\n" ); document.write( "\"+2s+=+360+\"
\n" ); document.write( "\"+s+=+180+\"
\n" ); document.write( "And
\n" ); document.write( "(1) \"+195+=+180+%2B+w+\"
\n" ); document.write( "(1) \"+w+=+15+\"
\n" ); document.write( "————————————-
\n" ); document.write( "Check:
\n" ); document.write( "(2) \"+330+=+%28+s-w+%29%2A2+\"
\n" ); document.write( "(2) \"+330+=+165%2A2+\"
\n" ); document.write( "(2) \"+330+=+330+\"
\n" ); document.write( "OK\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
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