document.write( "Question 186418: An Airplane flew for 4 hours against headwind of 40 km/h. On the
\n" ); document.write( "return flight the same wind was now a tail wind, and the flight took 3
\n" ); document.write( "hours. Find the speed of the airplane in still air \n" ); document.write( "

Algebra.Com's Answer #139708 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"p\"$ = speed of plane in still air
\n" ); document.write( "Let $\"d\"$ = distance travelled one way
\n" ); document.write( "given:
\n" ); document.write( " $\"d+=+%28p+-+40%29%2A4\"$ (against wind)
\n" ); document.write( " $\"d+=+%28p+%2B+40%29%2A3\"$ (with wind)
\n" ); document.write( "Since both are equal to $\"d\"$ , set them
\n" ); document.write( "equal to eachother
\n" ); document.write( " $\"%28p+-+40%29%2A4+=+%28p+%2B+40%29%2A3\"$
\n" ); document.write( " $\"4p+-+160+=+3p+%2B+120\"$
\n" ); document.write( " $\"p+=+280\"$
\n" ); document.write( "The speed of plane in still air is 280 mi/hr
\n" ); document.write( "check:
\n" ); document.write( " $\"d+=+%28p+-+40%29%2A4\"$
\n" ); document.write( " $\"d+=+%28p+%2B+40%29%2A3\"$
\n" ); document.write( "-------------------
\n" ); document.write( " $\"d+=+%28280+-+40%29%2A4\"$
\n" ); document.write( " $\"d+=+240%2A4\"$
\n" ); document.write( " $\"d+=+960\"$
\n" ); document.write( " $\"d+=+%28p+%2B+40%29%2A3\"$
\n" ); document.write( " $\"d+=+%28280+%2B+40%29%2A3\"$
\n" ); document.write( " $\"d+=+320%2A3\"$
\n" ); document.write( " $\"d+=+960\"$
\n" ); document.write( "OK \n" ); document.write( "

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