document.write( "Question 162015: The Metro Rail travels 240 km at a uniform rate.If the speed had been 8 km per hour more,the journey would have taken 1 hour less.what is the speed of the train? \n" ); document.write( "

Algebra.Com's Answer #119435 by josmiceli(19441) $\"\"$ $\"About$

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$\"d+=+r%2At\"$
\n" ); document.write( "Given:
\n" ); document.write( " $\"d+=+240\"$ km
\n" ); document.write( "If the speed was $\"r+%2B+8\"$ km/hr
\n" ); document.write( "the time would have been $\"t+-+1\"$ hr
\n" ); document.write( "The equations are:
\n" ); document.write( " $\"240+=+r%2At\"$ and
\n" ); document.write( " $\"240+=+%28r+%2B+8%29%2A%28t+-+1%29\"$
\n" ); document.write( " $\"240+=+rt+%2B+8t+-+r+-+8\"$
\n" ); document.write( "And, since $\"240+=+r%2At\"$ ,
\n" ); document.write( " $\"240+=+240+%2B+8t+-+r+-+8\"$
\n" ); document.write( "Subtract $\"240\"$ from both sides
\n" ); document.write( " $\"0+=+8t+-+r+-+8\"$
\n" ); document.write( " $\"r+=+8%2A%28t+-+1%29\"$
\n" ); document.write( "Substitute this in $\"240+=+r%2At\"$
\n" ); document.write( " $\"240+=+8%2A%28t+-+1%29%2At\"$
\n" ); document.write( " $\"240+=+8t%5E2+-+8t\"$
\n" ); document.write( "Divide both sides by $\"8\"$
\n" ); document.write( " $\"t%5E2+-+t+-+30+=+0\"$
\n" ); document.write( " $\"%28t+-+6%29%28t+%2B+5%29+=+0\"$
\n" ); document.write( " $\"t+=+-5\"$
\n" ); document.write( " $\"t+=+6\"$ hrs
\n" ); document.write( " $\"240+=+r%2At\"$
\n" ); document.write( " $\"r+=+240+%2F+t\"$
\n" ); document.write( " $\"r+=+240%2F6\"$
\n" ); document.write( " $\"r+=+40\"$ km/hr
\n" ); document.write( "The speed of the train was 40 km/hr
\n" ); document.write( "check answer:
\n" ); document.write( " $\"240+=+r%2At\"$
\n" ); document.write( " $\"240+=+%28r+%2B+8%29%2A%28t+-+1%29\"$
\n" ); document.write( " $\"240+=+%2840+%2B+8%29%2A%286+-+1%29\"$
\n" ); document.write( " $\"240+=+48%2A5\"$
\n" ); document.write( " $\"240+=+240\"$
\n" ); document.write( "OK \n" ); document.write( "

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