document.write( "Question 483854: A train moving at uniform speed takes 20 seconds to pass a cyclist riding at 11 km/hr but only 9 seconds to pass a post. find its length. \n" ); document.write( "
Algebra.Com's Answer #331166 by ankor@dixie-net.com(22740)\"\" \"About 
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A train moving at uniform speed takes 20 seconds to pass a cyclist riding at 11 km/hr but only 9 seconds to pass a post.
\n" ); document.write( " find it's length.
\n" ); document.write( ":
\n" ); document.write( "change 11 km/hr to meter/sec
\n" ); document.write( "\"%2811%2A1000%29%2F%2860%2A60%29\" = 3.056 m/sec
\n" ); document.write( ":
\n" ); document.write( "Let L = length of train in meters
\n" ); document.write( "Let s = speed of train in m/sec
\n" ); document.write( ":
\n" ); document.write( "Using the post as ref:
\n" ); document.write( "L = 9s is the length of the train in meters
\n" ); document.write( ":
\n" ); document.write( "Using the bike going 3.056 m/sec, as ref
\n" ); document.write( "L = 20(s - 3.056) is the length of the train
\n" ); document.write( ":
\n" ); document.write( "We can find s:
\n" ); document.write( "20(s - 3.056) = 9s
\n" ); document.write( "20s - 61.11 = 9s
\n" ); document.write( "20s - 9s = 61.11
\n" ); document.write( "11s = 61.11
\n" ); document.write( "s = \"61.11%2F11\"
\n" ); document.write( "s = 5.56 m/sec is the speed of the train
\n" ); document.write( "then
\n" ); document.write( "9 * 5.56 = 50 meters is the length of the train (post as ref)
\n" ); document.write( "and
\n" ); document.write( "20(5.56-3.056) ~ 50 meters also using a moving bike as ref \n" ); document.write( "
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