document.write( "Question 127073: Car A runs 30kmph less than Car B. Car A covers 250 km in the same time Car B travels 400 km. What are the rates of each car? \n" ); document.write( "

Algebra.Com's Answer #93097 by josmiceli(19441) $\"\"$ $\"About$

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car A: $\"d%5Ba%5D+=+r%5Ba%5D%2At%5Ba%5D\"$
\n" ); document.write( "car B: $\"d%5Bb%5D+=+r%5Bb%5D%2At%5Bb%5D\"$
\n" ); document.write( "given: $\"t%5Ba%5D+=+t%5Bb%5D\"$
\n" ); document.write( " $\"d%5Ba%5D+=+250\"$ km
\n" ); document.write( " $\"d%5Bb%5D+=+400\"$ km
\n" ); document.write( " $\"r%5Ba%5D+=+r%5Bb%5D+-+30\"$ km/hr
\n" ); document.write( "putting all this together:
\n" ); document.write( "car A: $\"250+=+%28r%5Bb%5D-+30%29%2At\"$
\n" ); document.write( "car B: $\"400+=+r%5Bb%5D%2At\"$
\n" ); document.write( "solve each one for $\"t\"$
\n" ); document.write( " $\"t+=+250+%2F+%28r%5Bb%5D+-+30%29\"$
\n" ); document.write( " $\"t+=+400+%2F+r%5Bb%5D\"$
\n" ); document.write( "Set these equal to eachother
\n" ); document.write( " $\"250+%2F+%28r%5Bb%5D+-+30%29+=+400+%2F+r%5Bb%5D\"$
\n" ); document.write( "multiply both sides by $\"r%5Bb%5D%2A%28r%5Bb%5D+-+30%29\"$
\n" ); document.write( " $\"250%2Ar%5Bb%5D+=+400%2A%28r%5Bb%5D+-+30%29\"$
\n" ); document.write( " $\"150%2Ar%5Bb%5D+=+12000\"$
\n" ); document.write( " $\"r%5Bb%5D+=+80\"$
\n" ); document.write( " $\"r%5Ba%5D+=+r%5Bb%5D+-+30\"$
\n" ); document.write( " $\"r%5Ba%5D+=+50\"$
\n" ); document.write( "The rate of car A is 50 km/hr
\n" ); document.write( "The rate of car B is 80 km/hr
\n" ); document.write( "check answer
\n" ); document.write( " $\"t+=+250+%2F+%28r%5Bb%5D+-+30%29\"$
\n" ); document.write( " $\"t+=+400+%2F+r%5Bb%5D\"$
\n" ); document.write( "--------------------------
\n" ); document.write( " $\"t+=+250+%2F+50\"$
\n" ); document.write( " $\"t+=+5\"$ hrs
\n" ); document.write( " $\"t+=+400+%2F+80\"$
\n" ); document.write( " $\"t+=+5\"$ hrs
\n" ); document.write( "OK \n" ); document.write( "

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