document.write( "Question 576149: Without any wind an airplane flies at 200 miles per hour. It travels 800 miles into the wind and then returns with the wind in a total time of 8 hours and 20 minutes. Find the average speed of the wind? \n" ); document.write( "
Algebra.Com's Answer #369746 by lwsshak3(11628)\"\" \"About 
You can put this solution on YOUR website!
Without any wind an airplane flies at 200 miles per hour. It travels 800 miles into the wind and then returns with the wind in a total time of 8 hours and 20 minutes. Find the average speed of the wind?
\n" ); document.write( "**
\n" ); document.write( "let x = speed of the wind
\n" ); document.write( "200+x = speed of plane with the wind
\n" ); document.write( "200-x = speed of plane into the wind
\n" ); document.write( "Travel time = Distance/speed
\n" ); document.write( "800/(200-x)+800/(200+x)=8-1/3=25/3
\n" ); document.write( "LCD:3(200-x)(200+x)
\n" ); document.write( "3*800(200+x)+3*800(200-x)=25(200-x)(200+x)
\n" ); document.write( "2400(200+x+200-x)=25(200-x)(200+x)
\n" ); document.write( "2400*400=25(200^2-x^2)
\n" ); document.write( "divide by 25
\n" ); document.write( "38400=40000-x^2
\n" ); document.write( "x^2=1600
\n" ); document.write( "x=40
\n" ); document.write( "ans:
\n" ); document.write( "speed of the wind=40 mph\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
\n" );