document.write( "Question 162271: a helicopter travels 630 kms. at the same time that a car travels 210 kms. If the helicopter travels 60 km. per hour faster than the car, how fast does each of them travel? \n" ); document.write( "

Algebra.Com's Answer #119599 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"d+=+r%2At\"$ for both and
\n" ); document.write( " $\"t\"$ is the same for both
\n" ); document.write( " $\"r%5Bh%5D+=+r%5Bc%5D+%2B+60\"$
\n" ); document.write( "For helicopter:
\n" ); document.write( " $\"630+=+r%5Bh%5D%2At\"$
\n" ); document.write( " $\"630+=+%28r%5Bc%5D+%2B+60%29%2At\"$
\n" ); document.write( "For car:
\n" ); document.write( " $\"210+=+r%5Bc%5D%2At\"$
\n" ); document.write( "------------------
\n" ); document.write( "For helicopter:
\n" ); document.write( " $\"t+=+630+%2F+%28r%5Bc%5D+%2B+60%29\"$
\n" ); document.write( "For car:
\n" ); document.write( " $\"t+=+210+%2F+r%5Bc%5D\"$
\n" ); document.write( "The time, $\"t\"$ is the same for both, so
\n" ); document.write( " $\"630+%2F+%28r%5Bc%5D+%2B+60%29+=+210+%2F+r%5Bc%5D\"$
\n" ); document.write( "Multiply both sides by $\"r%5Bc%5D%2A%28r%5Bc%5D+%2B+60%29\"$
\n" ); document.write( " $\"630r%5Bc%5D+=+210%2A%28r%5Bc%5D+%2B+60%29\"$
\n" ); document.write( " $\"630r%5Bc%5D+=+210r%5Bc%5D+%2B+12600\"$
\n" ); document.write( " $\"420r%5Bc%5D+=+12600\"$
\n" ); document.write( " $\"r%5Bc%5D+=+30\"$ km/hr
\n" ); document.write( "and, since
\n" ); document.write( " $\"r%5Bh%5D+=+r%5Bc%5D+%2B+60\"$
\n" ); document.write( " $\"r%5Bh%5D+=+90\"$ km/hr
\n" ); document.write( "The car travels 30 km/hr and the helicopter
\n" ); document.write( "trvels 90 km/hr
\n" ); document.write( "check:
\n" ); document.write( " $\"630+%2F+%28r%5Bc%5D+%2B+60%29+=+210+%2F+r%5Bc%5D\"$
\n" ); document.write( " $\"630+%2F+%2830+%2B+60%29+=+210+%2F+30\"$
\n" ); document.write( " $\"63%2F9+=+21%2F3\"$
\n" ); document.write( " $\"7+=+7\"$
\n" ); document.write( "OK \n" ); document.write( "

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