document.write( "Question 1058973: An airplane travels 300 km from Manila and back in 4 hours and 30 minutes. The wind speed is 10 kph, what is the speed of the plane in still air? \n" ); document.write( "

Algebra.Com's Answer #674038 by ikleyn(52812) $\"\"$ $\"About$

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\n" ); document.write( "An airplane travels 300 km from Manila and back in 4 hours and 30 minutes. The wind speed is 10 kph, what is the speed of the plane in still air?
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document.write( "Let \"u\" represents the airspeed of the plane, in miles per hour.\r\n" );
document.write( "Then its speed when flying with the wind is (u+10).\r\n" );
document.write( "Its speed when flying against the wind is (u-10).\r\n" );
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document.write( "The governing equation is\r\n" );
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document.write( " = 4.5.\r\n" );
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document.write( "The first addend on the left side is the time for flight with the wind.\r\n" );
document.write( "The second addend on the left side is the time for flight against the wind. \r\n" );
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document.write( "Solve it and find \"u\".\r\n" );
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document.write( "As the first step, multiply both sides of the equation by (u+10)*(u-10).\r\n" );
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document.write( "You will get a quadratic equation.\r\n" );
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document.write( "Simplify it, reduce to the standard form and then apply the quadratic formula.\r\n" );
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\n" ); document.write( "\n" ); document.write( "It is a typical \"tailwind and headwind\" word problem.\r
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\n" ); document.write( "\n" ); document.write( "See the lessons \r
\n" ); document.write( "\n" ); document.write( "    - Wind and Current problems \r
\n" ); document.write( "\n" ); document.write( "    - Wind and Current problems solvable by quadratic equations \r
\n" ); document.write( "\n" ); document.write( "    - Selected problems from the archive on a plane flying with and against the wind \r
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\n" ); document.write( "\n" ); document.write( "In these lessons you will find the detailed solutions of many similar problems. \r
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\n" ); document.write( "\n" ); document.write( "Also, you have this free of charge online textbook in ALGEBRA-I in this site\r
\n" ); document.write( "\n" ); document.write( "    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.\r
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\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this textbook under the section \"Word problems\", the topic \"Travel and Distance problems\".\r
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