![\"\"](\"/images/stars/stars-13.gif\")
You can put this solution on YOUR website!
A glider is traveling 240 kilometers in 3 hours with the wind. It travels 210 kilometers in 3 hours against the wind. What is the speed of the wind and the glider?
\n" ); document.write( ":
\n" ); document.write( "How does a glider go against the wind?
\n" ); document.write( ":
\n" ); document.write( "But assuming it is powered somehow, here is the solution:
\n" ); document.write( ":
\n" ); document.write( "Let x = speed of the plane
\n" ); document.write( "Let y = speed of the wind:
\n" ); document.write( "Then
\n" ); document.write( "(x+y) = ground speed with the wind
\n" ); document.write( "and
\n" ); document.write( "(x-y) = ground speed against the wind
\n" ); document.write( ":
\n" ); document.write( "Write two distance equations; Distance = time * speed
\n" ); document.write( ":
\n" ); document.write( "3(x+y) = 240; with the wind
\n" ); document.write( "3(x-y) = 210: against the wind
\n" ); document.write( ":
\n" ); document.write( "We can simplify both equations by dividing them by 3, leaving us with:
\n" ); document.write( "x + y = 80
\n" ); document.write( "x - y = 70
\n" ); document.write( "------------adding eliminates y; find x
\n" ); document.write( "2x + 0 = 150
\n" ); document.write( "x = 150/2
\n" ); document.write( "x = 75 km/hr speed of the \"glider\"
\n" ); document.write( ":
\n" ); document.write( "Find the wind speed
\n" ); document.write( "75 + y = 80
\n" ); document.write( "y = 80 - 75
\n" ); document.write( "y = 5 km/hr is the wind
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Check solutions in one of the original equations
\n" ); document.write( "3(75 - 5) =
\n" ); document.write( "3(70) = 210 km
\n" ); document.write( ":
\n" ); document.write( "Did this make sense? Any questions?\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "