document.write( "Question 895698: A plane traveled 644 miles to Austin and back. The trip there was with the wind. It took 7 hours. the trip back was into the wind. The trip took 14 hours. What is the speed of the plane in still air? What is the speed of the wind?\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "THANKS :] \n" ); document.write( "
Algebra.Com's Answer #542961 by lwsshak3(11628)\"\" \"About 
You can put this solution on YOUR website!
A plane traveled 644 miles to Austin and back. The trip there was with the wind. It took 7 hours. the trip back was into the wind. The trip took 14 hours. What is the speed of the plane in still air? What is the speed of the wind?
\n" ); document.write( "***
\n" ); document.write( "let x=speed of plane in still air
\n" ); document.write( "let c=speed of wind
\n" ); document.write( "x+c=speed of plane with wind
\n" ); document.write( "x-c=speed of plane into wind
\n" ); document.write( "Distance/speed=travel time
\n" ); document.write( "..
\n" ); document.write( "644/(x+c)=7
\n" ); document.write( "644/(x-c)=14
\n" ); document.write( "..
\n" ); document.write( "7x+7c=644
\n" ); document.write( "14x-14c=644
\n" ); document.write( "..
\n" ); document.write( "14x+14c=1288 (mult. by 2)
\n" ); document.write( "14x-14c=644
\n" ); document.write( "add
\n" ); document.write( "28x=1932
\n" ); document.write( "x=69
\n" ); document.write( "7c=644-7x
\n" ); document.write( "7c=161
\n" ); document.write( "c=23
\n" ); document.write( "speed of plane in still air=69 mph
\n" ); document.write( "speed of wind=23 mph \n" ); document.write( "
\n" );