document.write( "Question 185140: AN AIRPLANE FLEW FOR 4.23 HOURS WITH A 25.5KM/H TAIL WIND.
\n" ); document.write( "THE RETURN FLIGHT AGAINST THE SAME WIND TOOK 4.97HOURS.
\n" ); document.write( "FIND THE SPEED OF THE PLANE IN STILL WATER. \n" ); document.write( "
Algebra.Com's Answer #138905 by Alan3354(69443)\"\" \"About 
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AN AIRPLANE FLEW FOR 4.23 HOURS WITH A 25.5KM/H TAIL WIND.
\n" ); document.write( "THE RETURN FLIGHT AGAINST THE SAME WIND TOOK 4.97HOURS.
\n" ); document.write( "FIND THE SPEED OF THE PLANE IN STILL WATER.
\n" ); document.write( "---------------------------------
\n" ); document.write( "w = wind speed = 25.5
\n" ); document.write( "r = speed of plane
\n" ); document.write( "d = distance
\n" ); document.write( "d = rt
\n" ); document.write( "Upwind:
\n" ); document.write( "d = (r-25.5)*4.97
\n" ); document.write( "Downwind:
\n" ); document.write( "d = (r+25.5)*4.23
\n" ); document.write( "Distance is the same, so they equal each other
\n" ); document.write( "(r-25.5)*4.97 = (r+25.5)*4.23
\n" ); document.write( "4.97r - 4.97*25.5 = 4.23r + 4.23*25.5
\n" ); document.write( "0.74r = 25.5*9.20
\n" ); document.write( "r = 317.027 kph
\n" ); document.write( "-----------------
\n" ); document.write( "Planes don't use kilometers per hour, they use knots. So do boats.
\n" ); document.write( "I've flown seaplanes, and that's very fast for on the water. Maybe you meant in still air.
\n" ); document.write( " \n" ); document.write( "
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