document.write( "Question 673883: Two trains, one express and one local, leave Indianapolis at noon and head for Chicago 220 miles away. The express travels twice as fast as the local and arrives 2 hours ahead of the local. Find the speed of each train \n" ); document.write( "

Algebra.Com's Answer #418921 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+s+\"$ = the speed of the local train
\n" ); document.write( "Let $\"+t+\"$ = the travel time for the local train
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\n" ); document.write( "Equation for local train:
\n" ); document.write( "(1) $\"+220+=+s%2At+\"$
\n" ); document.write( "Equation for express train:
\n" ); document.write( "(2) $\"+220+=+2s%2A%28+t+-+2+%29+\"$
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\n" ); document.write( "(2) $\"+220+=+2%2As%2At+-+4s+\"$
\n" ); document.write( "Substitute (1) into (2)
\n" ); document.write( "(2) $\"+220+=+2%2A220+-+4s+\"$
\n" ); document.write( "(2) $\"+4s+=+440+-+220+\"$
\n" ); document.write( "(2) $\"+4s+=+220+\"$
\n" ); document.write( "(2) $\"+s+=+55+\"$
\n" ); document.write( " $\"+2s+=+110+\"$
\n" ); document.write( "The express train's speed is 110 m,i/hr
\n" ); document.write( "The local train's speed is 55 mi/hr
\n" ); document.write( "check answer:
\n" ); document.write( "(1) $\"+220+=+s%2At+\"$
\n" ); document.write( "(1) $\"+t+=+220%2F55+\"$
\n" ); document.write( "(1) $\"+t+=+4+\"$
\n" ); document.write( "and
\n" ); document.write( "(2) $\"+220+=+2s%2A%28+4+-+2+%29+\"$
\n" ); document.write( "(2) $\"+220+=+4s+\"$
\n" ); document.write( "(2) $\"+s+=+55+\"$
\n" ); document.write( "OK\r
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