document.write( "Question 1163676: Derek runs onto an escalator to the second floor, but the escalator is
\n" ); document.write( "moving downward. He runs 3 steps for each second. 30 seconds after he steps
\n" ); document.write( "on the escalator, Kenny runs onto this escalator with 4 steps per second.
\n" ); document.write( "The moving speed of the escalator is 1.5 steps/sec, and it has 150 steps.
\n" ); document.write( "How many steps left when Kenny catches up Derek? Round your answer to the
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Algebra.Com's Answer #787957 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
Derek runs onto an escalator to the second floor, but the escalator is
\n" ); document.write( "moving downward. He runs 3 steps for each second. 30 seconds after he steps
\n" ); document.write( "on the escalator, Kenny runs onto this escalator with 4 steps per second.
\n" ); document.write( "The moving speed of the escalator is 1.5 steps/sec, and it has 150 steps.
\n" ); document.write( "How many steps are left when Kenny catches up Derek? Round your answer to
\n" ); document.write( "the nearest whole number.\r
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\n" ); document.write( "\n" ); document.write( "The moving speed of the escalator is 1.5 steps/sec
\n" ); document.write( "He (Derek) runs 3 steps for each second.
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document.write( "If the escalator were stopped, Derek would be running 3 steps/second, but\r\n" );
document.write( "the escalator slows him down by its speed, so his speed is\r\n" );
document.write( "3-1.5=1.5 steps/second.\r\n" );
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\n" ); document.write( "30 seconds after he (Derek) steps on the escalator...
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document.write( "At this instant, using d=rt, Derek is 30(1.5)=45 steps up the escalator  \r\n" );
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\n" ); document.write( "...Kenny runs onto this escalator with 4 steps per second.
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document.write( "If the escalator were stopped, Kenny would be running 4 steps/second, but\r\n" );
document.write( "the escalator slows him down, so his speed is 4-1.5=2.5 steps/second.\r\n" );
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document.write( "Kenny's approach rate to Derek is the difference of their speeds which is\r\n" );
document.write( "(2.5)-(1.5)=1 step/second.\r\n" );
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\n" ); document.write( "How many steps left when Kenny catches up Derek?
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document.write( "Using t=d/r, since they are 45 steps apart, Kenny catches Derek in\r\n" );
document.write( "45/1=45 seconds.  At that instant, using d=rt, Kenney has traveled \r\n" );
document.write( "(2.5)(45) = 112.5 steps up the escalator, so there are 150-112.5=37.5 steps\r\n" );
document.write( "left.  \r\n" );
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\n" ); document.write( "Round your answer to the nearest whole number.
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document.write( "We round up to 113 steps. \r\n" );
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document.write( "Edwin
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