document.write( "Question 1050351: A man flies a small airplane from Fargo to Bismarck, North Dakota --- a distance of 180 miles. Because he is flying into a head wind, the trip takes him 2 hours. On the way back, the wind is still blowing at the same speed, so the return trip takes only 1 hour 12 minutes. What is his speed in still air, and how fast is the wind blowing?
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Algebra.Com's Answer #665918 by advanced_Learner(501) $\"\"$ $\"About$

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solve\r
\n" ); document.write( "\n" ); document.write( "90=u-v\r
\n" ); document.write( "\n" ); document.write( "150=u+v\r
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Solved by pluggable solver: SOLVE linear system by SUBSTITUTION

Solve:
\n" ); document.write( " $\"+system%28+%0D%0A++++1%5Cu+%2B+-1%5Cv+=+90%2C%0D%0A++++1%5Cu+%2B+1%5Cv+=+150+%29%0D%0A++\"$ We'll use substitution. After moving -1*v to the right, we get:
\n" ); document.write( " $\"1%2Au+=+90+-+-1%2Av\"$ , or $\"u+=+90%2F1+-+-1%2Av%2F1\"$ . Substitute that
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\n" ); document.write( " $\"1%2A%2890%2F1+-+-1%2Av%2F1%29+%2B+1%5Cv+=+150\"$ and simplify: So, we know that v=30. Since $\"u+=+90%2F1+-+-1%2Av%2F1\"$ , u=120.
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\n" ); document.write( " Answer: $\"system%28+u=120%2C+v=30+%29\"$ .
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