document.write( "Question 253133: abu ran for 1/3 of an hour and then walked for half an hour at the rate of 3km/h. in all, he had covered 4 km. how fast did he run? \n" ); document.write( "

Algebra.Com's Answer #185369 by josmiceli(19441) $\"\"$ $\"About$

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Write 2 equations,1 for running
\n" ); document.write( "and 1 for walking
\n" ); document.write( " $\"d%5Br%5D+=+r%5Br%5D%2At%5Br%5D\"$
\n" ); document.write( "and
\n" ); document.write( " $\"d%5Bw%5D+=+r%5Bw%5D%2At%5Bw%5D\"$
\n" ); document.write( "given:
\n" ); document.write( " $\"t%5Br%5D+=+1%2F3\"$ hr
\n" ); document.write( " $\"t%5Bw%5D+=+1%2F2\"$ hr
\n" ); document.write( " $\"r%5Bw%5D+=+3\"$ km/hr
\n" ); document.write( " $\"d%5Br%5D+%2B+d%5Bw%5D+=+4\"$ km
\n" ); document.write( "-----------------
\n" ); document.write( " $\"d%5Br%5D+=+r%5Br%5D%2At%5Br%5D\"$
\n" ); document.write( " $\"d%5Br%5D+=r%5Br%5D%2A%281%2F3%29\"$
\n" ); document.write( "and
\n" ); document.write( " $\"4+-+d%5Br%5D+=+3%2A%281%2F2%29\"$
\n" ); document.write( " $\"-d%5Br%5D+=+3%2F2+-+4\"$
\n" ); document.write( " $\"-d%5Br%5D+=+-5%2F2\"$
\n" ); document.write( " $\"d%5Br%5D+=+5%2F2\"$
\n" ); document.write( "and, since
\n" ); document.write( " $\"d%5Br%5D+=r%5Br%5D%2A%281%2F3%29\"$
\n" ); document.write( " $\"5%2F2+=+r%5Br%5D%2A%281%2F3%29\"$
\n" ); document.write( " $\"r%5Br%5D+=+15%2F2\"$
\n" ); document.write( "He ran 7.5 km/hr
\n" ); document.write( "check:
\n" ); document.write( " $\"d%5Br%5D+=+r%5Br%5D%2At%5Br%5D\"$
\n" ); document.write( " $\"5%2F2+=+%2815%2F2%29%2A%281%2F3%29\"$
\n" ); document.write( " $\"5%2F2+=+5%2F2\"$
\n" ); document.write( "OK \n" ); document.write( "

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