document.write( "Question 623037: an airplane makes a 990 km flight with a tailwind and returns, flying into the same wind.The total flying time is 3hrs 20 mins and the airplanes speed in still air is600 km/h
\n" ); document.write( "what is the speed of the wind.
\n" ); document.write( " I have the total distance travelled to be 990+990=1980
\n" ); document.write( "Total time 200 min rtn or 100 min each way\r
\n" ); document.write( "\n" ); document.write( "Then I am stuck \n" ); document.write( "
Algebra.Com's Answer #391814 by lwsshak3(11628)\"\" \"About 
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an airplane makes a 990 km flight with a tailwind and returns, flying into the same wind.The total flying time is 3hrs 20 mins and the airplanes speed in still air is 600 km/h
\n" ); document.write( "what is the speed of the wind.
\n" ); document.write( "**
\n" ); document.write( "let x=speed of wind
\n" ); document.write( "600+x=speed of plane with tail wind
\n" ); document.write( "600-x=speed of plane into wind
\n" ); document.write( "Total flying time=3hr+20min=20+1/3 hr=10/3 hr
\n" ); document.write( "Travel time = distance/speed
\n" ); document.write( "..
\n" ); document.write( "990/(600+x)+990/(600-x)=10/3
\n" ); document.write( "LCD:3(600+x)(600-x)
\n" ); document.write( "3*990(600-x)+3*990(600+x)=10(600+x)(600-x)
\n" ); document.write( "3*990(600+x+600-x)=10(360000-x^2)
\n" ); document.write( "(3*990*1200)/10=360000-x^2
\n" ); document.write( "356400=360000-x^2
\n" ); document.write( "x^2=360000-356400
\n" ); document.write( "x^2=3600
\n" ); document.write( "x=√(3600)
\n" ); document.write( "x=60
\n" ); document.write( "speed of wind=60 km/hr
\n" ); document.write( " \n" ); document.write( "
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