document.write( "Question 1138286: 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? \n" ); document.write( "

Algebra.Com's Answer #756115 by ikleyn(52781) $\"\"$ $\"About$

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document.write( "Let d be the distance from the epicenter of the earthquake to the station (in kilometers).\r\n" );
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document.write( "For P-wave, the traveling time is   seconds.\r\n" );
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document.write( "For S-wave, the traveling time is   seconds.\r\n" );
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document.write( "The difference is\r\n" );
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document.write( "     -  = 40  seconds.\r\n" );
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document.write( "It is your \"time\" equation.\r\n" );
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document.write( "To solve it, multiply all terms by 15 = 3*5.  You will get\r\n" );
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document.write( "    5d - 3d = 15*40\r\n" );
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document.write( "    2d = 600\r\n" );
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document.write( "    d = 300 kilometers.\r\n" );
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document.write( "ANSWER.  The distance from the epicenter of the earthquake to the station is 300 kilometers.\r\n" );
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\n" ); document.write( "\n" ); document.write( "From my post, lean on how to write, to solve and to use a \"time\" equation.\r
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\n" ); document.write( "\n" ); document.write( "To see many other similar solved problems, look into the lessons\r
\n" ); document.write( "\n" ); document.write( "    - Earthquake waves \r
\n" ); document.write( "\n" ); document.write( "    - Had a car move faster it would arrive sooner\r
\n" ); document.write( "\n" ); document.write( "    - How far do you live from school? \r
\n" ); document.write( "\n" ); document.write( "in this site.\r
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\n" ); document.write( "\n" ); document.write( "Also, you have this free of charge online textbook in ALGEBRA-I in this site\r
\n" ); document.write( "\n" ); document.write( "    ALGEBRA-I - YOUR ONLINE TEXTBOOK.\r
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\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this textbook under the section \"Word problems\", the topic \"Travel and Distance problems\".\r
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\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Save the link to this online textbook together with its description\r
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\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-I
\n" ); document.write( "https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson\r
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\n" ); document.write( "\n" ); document.write( "to your archive and use it when it is needed.\r
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