document.write( "Question 69722: Find the rate of two cars traveling in the same direction if they leave the same place at the same. The rate of one is twice as fast as the other, and after 4 hours the faster car is 80 miles ahead of the slower car.\r
\n" ); document.write( "\n" ); document.write( "Formula for solving motion problems is rt=d \n" ); document.write( "

Algebra.Com's Answer #49668 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
I like to use subscripts with these kind of problems
\n" ); document.write( " $\"d%5B1%5D+=+r%5B1%5D%2At\"$
\n" ); document.write( " $\"d%5B2%5D+=+r%5B2%5D%2At\"$
\n" ); document.write( "time will be common to both equations (4 hours)
\n" ); document.write( "The problems says
\n" ); document.write( " $\"d%5B2%5D+=+d%5B1%5D+%2B+80\"$ at t = 4
\n" ); document.write( "and
\n" ); document.write( " $\"r%5B2%5D+=+2%2Ar%5B1%5D\"$
\n" ); document.write( "continuing
\n" ); document.write( " $\"d%5B1%5D+=+r%5B1%5D%2A4\"$
\n" ); document.write( " $\"d%5B1%5D+%2B+80+=+2%2Ar%5B1%5D%2A4\"$
\n" ); document.write( "substituting
\n" ); document.write( " $\"r%5B1%5D%2A4+%2B+80+=+8%2Ar%5B1%5D\"$
\n" ); document.write( " $\"4%2Ar%5B1%5D+=+80\"$
\n" ); document.write( " $\"r%5B1%5D+=+20\"$ mi/hr answer
\n" ); document.write( " $\"r%5B2%5D+=+40\"$ mi/hr answer
\n" ); document.write( " $\"d%5B1%5D+=+80\"$ mi
\n" ); document.write( " $\"d%5B2%5D+=+160\"$ mi\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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