document.write( "Question 231060: An elevator went from the bottom to the top of a tower at an average speed of 4m/s, remained at the top for 90 s, and then returned to the bottom at 5 m/s. If the total elapsed was 4.5 min, how high is the tower? \n" ); document.write( "
Algebra.Com's Answer #171318 by ankor@dixie-net.com(22740)\"\" \"About 
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An elevator went from the bottom to the top of a tower at an average speed of
\n" ); document.write( " 4m/s, remained at the top for 90 s, and then returned to the bottom at 5 m/s.
\n" ); document.write( " If the total elapsed was 4.5 min, how high is the tower?
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\n" ); document.write( "Change 4.5 min to 270 sec
\n" ); document.write( "Elevator travel time,(remains at top for 90 sec):
\n" ); document.write( "270 - 90 = 180 sec
\n" ); document.write( ":
\n" ); document.write( "Let t = time for elevator to go to the top
\n" ); document.write( "Then
\n" ); document.write( "(180-t) = time to return to bottom
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\n" ); document.write( "Write a distance (height) equation: dist = speed * time
\n" ); document.write( "Dist up = dist down
\n" ); document.write( "4t = 5(180-t)
\n" ); document.write( "4t = 900 - 5t
\n" ); document.write( "4t + 5t = 900
\n" ); document.write( "9t = 900
\n" ); document.write( "t = 100 sec
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\n" ); document.write( "Use this value to find the dist up:
\n" ); document.write( "4 * 100 = 400 meters high
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\n" ); document.write( "Check solution using return equation
\n" ); document.write( "5(180 - 100) = 400 meter high \n" ); document.write( "
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