document.write( "Question 967353: A car leaves Hartford traveling north at 56 km/h. Another car leaves Hartford one hour later traveling north on the same road at 84 km/h. How far from Hartford will the second car overtake and pass the first car? \n" ); document.write( "

Algebra.Com's Answer #591239 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
What is the 1st car's head start?
\n" ); document.write( " $\"+d%5B1%5D+=+56%2A1+\"$
\n" ); document.write( " $\"+d%5B1%5D+=+56+\"$ km
\n" ); document.write( "------------------
\n" ); document.write( "Start a stopwatch when the 2nd car leaves Hartford
\n" ); document.write( "Let $\"+d+\"$ = distance in km 2nd car travels
\n" ); document.write( "until it catches 1st car
\n" ); document.write( "Let $\"+t+\"$ = time in hrs on stopwatch when 2nd
\n" ); document.write( "car catches 1st car
\n" ); document.write( "-----------------
\n" ); document.write( "Equation for 1st car:
\n" ); document.write( "(1) $\"+d+-+56+=+56t+\"$
\n" ); document.write( "Equation for 2nd car:
\n" ); document.write( "(2) $\"+d+=+84t+\"$
\n" ); document.write( "--------------------
\n" ); document.write( "By substitution:
\n" ); document.write( " $\"+84t+-+56+=+56t+\"$
\n" ); document.write( " $\"+28t+=+56+\"$
\n" ); document.write( " $\"+t+=+2+\"$ hrs
\n" ); document.write( "and
\n" ); document.write( "(2) $\"+d+=+84%2A2+\"$
\n" ); document.write( "(2) $\"+d+=+168+\"$
\n" ); document.write( "168 km from Hartford the 2nd car overtakes the 1st
\n" ); document.write( "------------
\n" ); document.write( "check:
\n" ); document.write( "(1) $\"+d+-+56+=+56t+\"$
\n" ); document.write( "(1) $\"+168+-+56+=+56%2A2+\"$
\n" ); document.write( "(1) $\"+112+=+112+\"$
\n" ); document.write( "OK\r
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