document.write( "Question 870939: -
\n" ); document.write( "I am confused how to work this problem.\r
\n" ); document.write( "\n" ); document.write( "An airplane can fly downwind a distance of 800 miles in 1.6 hours. The return trip against the same wind takes 2 hours. Find the speed of the wind. \n" ); document.write( "

Algebra.Com's Answer #525237 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+s+\"$ = the speed of the plane in still air
\n" ); document.write( "Let $\"+w+\"$ = the speed of the wind
\n" ); document.write( "--------------------------------
\n" ); document.write( "Flying down wind:
\n" ); document.write( "(1) $\"+800+=+%28+s+%2B+w+%29%2A1.6+\"$
\n" ); document.write( "Flying upwind:
\n" ); document.write( "(2) $\"+800+=+%28+s+-+w+%29%2A2+\"$
\n" ); document.write( "-----------------------
\n" ); document.write( "(1) $\"+1.6s+%2B+1.6w+=+800+\"$
\n" ); document.write( "(1) $\"+16s+%2B+16w+=+8000+\"$
\n" ); document.write( "and
\n" ); document.write( "(2) $\"+2s+-+2w+=+800+\"$
\n" ); document.write( "-----------------------
\n" ); document.write( "Multiply both sides of (2) by $\"+8+\"$
\n" ); document.write( "and subtract (2) from (1)
\n" ); document.write( "(1) $\"+16s+%2B+16w+=+8000+\"$
\n" ); document.write( "(2) $\"+-16s+%2B+16w+=+-6400+\"$
\n" ); document.write( " $\"+32w+=+1600+\"$
\n" ); document.write( " $\"+w+=+50+\"$
\n" ); document.write( "The windspeed is 50 mi/hr
\n" ); document.write( "-------------------------
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+800+=+%28+s+-+w+%29%2A2+\"$
\n" ); document.write( "(2) $\"+800+=+%28+s+-+50+%29%2A2+\"$
\n" ); document.write( "(2) $\"+800+=+2s+-+100+\"$
\n" ); document.write( "(2) $\"+2s+=+900+\"$
\n" ); document.write( "(2) $\"+s+=+450+\"$
\n" ); document.write( "and
\n" ); document.write( "(1) $\"+800+=+%28+s+%2B+w+%29%2A1.6+\"$
\n" ); document.write( "(1) $\"+800+=+%28+450+%2B+50+%29%2A1.6+\"$
\n" ); document.write( "(1) $\"+800+=+500%2A1.6+\"$
\n" ); document.write( "(1) $\"+800+=+800+\"$
\n" ); document.write( "OK\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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