document.write( "Question 551399: Schools often have a section of street called a school zone located near their entrances. In a school zone, driving speeds are reduced at certain times of the day. If a school zone is 0.3 miles long, how many minutes longer does it take to drive through it at 20 miles per hour that at 30 miles per hour? \n" ); document.write( "

Algebra.Com's Answer #359707 by Earlsdon(6294) $\"\"$ $\"About$

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Starting with:
\n" ); document.write( " $\"d+=+rt\"$ d = distance, r = rate/speed, and t = time of travel.
\n" ); document.write( "For this problem, we want to find the difference in the times when r = 20mph and r = 30mph over a distance of 0.3 miles.
\n" ); document.write( "At 30mph we have:
\n" ); document.write( " $\"t%5B1%5D+=+0.3%2F30\"$
\n" ); document.write( " $\"t%5B1%5D+=0.01\"$ hours.
\n" ); document.write( "At 20mph we have:
\n" ); document.write( " $\"t%5B2%5D+=+0.3%2F20\"$
\n" ); document.write( " $\"t%5B2%5D+=+0.015\"$ hours. Subtract $\"t%5B2%5D-t%5B1%5D\"$
\n" ); document.write( " $\"0.015-0.01+=+0.005\"$ hours. Convert to seconds, multiply by 3600 seconds/hour.
\n" ); document.write( " $\"0.005%283600%29+=+18\"$ seconds.
\n" ); document.write( "It takes 18 seconds longer at 20mph than it would at 30mph. \n" ); document.write( "

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