document.write( "Question 30288: An airplane flew for 4 hours against a head wind of 40 km/h. On the return flight the same wind was now a tail wind, and the flight took 4 hours. find the speed of the airplane in still air. \n" ); document.write( "

Algebra.Com's Answer #16953 by Paul(988) $\"\"$ $\"About$

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Let the speed of the plane be x
\n" ); document.write( "Equation:
\n" ); document.write( " $\"x%2F4%2Bx%2F4=40\"$
\n" ); document.write( "Multiply the whole equation by 4 to remove the fraction and simplify:
\n" ); document.write( "2x=160
\n" ); document.write( "x=80\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "

Hence, the speed of the plane in still air is 80mph.
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document.write( "Paul. \n" );
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