document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1134751>Question 1134751</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Seismographs can record two types of wave energy (P waves and S waves) that travel through the Earth after an earthquake. Traveling through granite, P waves travel approximately 5 km/sec and S waves travel approximately 3 km/sec. If a geologist working at a seismic station measures a time difference of 40 sec between an earthquake's P waves and S waves, how far from the epicenter of the earthquake is the station? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #752225 by </B><A HREF=/tutors/aboutme.mpl?userid=rothauserc><B>rothauserc(4718)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=rothauserc><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=rothauserc><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=752225\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> rate * time = distance<BR>\n" );
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document.write( "let t be the time for P waves to travel the distance, then t+40 is the time for S waves<BR>\n" );
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document.write( "5 * t = 3 * (t + 40)<BR>\n" );
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document.write( "5t = 3t +120<BR>\n" );
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document.write( "2t = 120<BR>\n" );
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document.write( "t = 60 seconds<BR>\n" );
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document.write( "The station is 5 * 60 = 300 km from the epicenter<BR>\n" );
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