document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1205494>Question 1205494</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The speed of light is 300,000km/sec and the planet Pluto is located at a distance of 6 billion km from Earth. If a spaceship, traveling at a constant speed in a straight line, goes from Earth to Pluto in 100 hours, at what fraction of the speed of light is this spaceship travelling? Thank You!<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #842343 by </B><A HREF=/tutors/aboutme.mpl?userid=math_tutor2020><B>math_tutor2020(3817)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=math_tutor2020><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=842343\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <font color=black size=3><BR>\n" );
document.write( "300,000 = 3*10^5<BR>\n" );
document.write( "6 billion = 6*10^9\r<BR>\n" );
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document.write( "1 hour = 60*60 = 3600 seconds<BR>\n" );
document.write( "100 hours = 100*3600 = 360,000 seconds<BR>\n" );
document.write( "360,000 = 3.6*10^5\r<BR>\n" );
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document.write( "Determine the speed of the spaceship<BR>\n" );
document.write( "distance = rate*time<BR>\n" );
document.write( "rate = distance/time<BR>\n" );
document.write( "rate = (6*10^9 km)/(3.6*10^5 seconds)<BR>\n" );
document.write( "rate = (6/3.6)*((10^9)/(10^5)) km per second<BR>\n" );
document.write( "rate = (60/36)*10^4 km per second<BR>\n" );
document.write( "rate = (5/3)*10^4 km per second\r<BR>\n" );
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document.write( "Divide this over the speed of light to wrap things up<BR>\n" );
document.write( "( spaceship's speed )/( speed of light )<BR>\n" );
document.write( "( (5/3)*10^4 )/( 3*10^5 )<BR>\n" );
document.write( "( (5/3)*10^4 )/( 3*10*10^4 )<BR>\n" );
document.write( "( (5/3)*10^4 )/( 30*10^4 )<BR>\n" );
document.write( "( (5/3)/30 )*((10^4)/(10^4))<BR>\n" );
document.write( "(5/3)/30<BR>\n" );
document.write( "(5/3)*(1/30)<BR>\n" );
document.write( "5/90<BR>\n" );
document.write( "<font color=red>1/18</font> is the final answer.\r<BR>\n" );
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document.write( "Another approach\r<BR>\n" );
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document.write( "Let's see how long it takes a light beam to go from Earth to Pluto<BR>\n" );
document.write( "distance = rate*time<BR>\n" );
document.write( "time = distance/rate<BR>\n" );
document.write( "time = (6*10^9 km)/(3*10^5 km per sec)<BR>\n" );
document.write( "time = (6/3)*((10^9)/(10^5)) sec<BR>\n" );
document.write( "time = 2*10^4 sec<BR>\n" );
document.write( "time = 20,000 sec\r<BR>\n" );
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document.write( "Divide this over 360,000 seconds (the time it takes the spaceship to reach Pluto) and you should get the fraction <font color=red>1/18</font><BR>\n" );
document.write( "It represents the idea that the light beam can travel to Pluto 18 times in the same timespan the spaceship travels.<BR>\n" );
document.write( "In other words, the light beam travels 18/2 = 9 round trips from Earth to Pluto, and back. In these 9 round trips of the light beam, the spaceship will arrive at Pluto.\r<BR>\n" );
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document.write( "Answer:  <font color=red>1/18</font><BR>\n" );
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