document.write( "Question 768994: Two race cars start from the same place and race off in the same direction. The speeds of the two cars are 10 and 60 mph respectively. How far from the starting point will the two meet if the second car left 10 hours after the first car? \n" ); document.write( "

Algebra.Com's Answer #468612 by josmiceli(19441) $\"\"$ $\"About$

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What is the 1st car's head start?
\n" ); document.write( " $\"+d%5B1%5D+=+10%2A10+=+100+\"$ mi
\n" ); document.write( "---------
\n" ); document.write( "Start a stopwatch when the 2nd car leaves
\n" ); document.write( "Let $\"+t+\"$ = the time on the stopwatch in
\n" ); document.write( "hours when they meet
\n" ); document.write( "Let $\"+d+\"$ = rhe distance in miles that the
\n" ); document.write( "2nd car travels in time $\"+t+\"$
\n" ); document.write( "---------
\n" ); document.write( "1st car's equation:
\n" ); document.write( "(1) $\"+d+-+100+=+10t+\"$
\n" ); document.write( "2nd car's equation:
\n" ); document.write( "(2) $\"+d+=+60t+\"$
\n" ); document.write( "--------------
\n" ); document.write( "By substitution:
\n" ); document.write( "(1) $\"+60t+-+100+=+10t+\"$
\n" ); document.write( "(1) $\"+50t+=+100+\"$
\n" ); document.write( "(1) $\"+t+=+2+\"$
\n" ); document.write( "and
\n" ); document.write( "(2) $\"+d+=+60%2A2+\"$
\n" ); document.write( "(2) $\"+d+=+120+\"$
\n" ); document.write( "The cars meet 120 miles from the starting point
\n" ); document.write( "------------
\n" ); document.write( "check:
\n" ); document.write( "(1) $\"+d+-+100+=+10t+\"$
\n" ); document.write( "(1) $\"+d+-+100+=+10%2A2+\"$
\n" ); document.write( "(1) $\"+d+=+120+\"$
\n" ); document.write( "OK
\n" ); document.write( " \n" ); document.write( "

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