document.write( "Question 1056985: Boris drove to the mountains last weekend. There was heavy traffic on the way there, and the trip took 7 hours. When Boris drove home, there was no traffic and the trip only took 4 hours. If his average rate was 27 miles per hour faster on the trip home, how far away does Boris live from the mountains? \n" ); document.write( "

Algebra.Com's Answer #672052 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+d+\"$ = the one-way distance to the mountains in miles
\n" ); document.write( "Let $\"+s+\"$ = his speed going to the mountains in mi/hr
\n" ); document.write( " $\"+s+%2B+27+\"$ = his speed on the trip home in mi/hr
\n" ); document.write( "-------------------------------------------------------
\n" ); document.write( "equation for going to the mountains:
\n" ); document.write( "(1) $\"+d+=+s%2A7+\"$
\n" ); document.write( "equation for going back home:
\n" ); document.write( "(2) $\"+d+=+%28+s+%2B+27+%29%2A4+\"$
\n" ); document.write( "---------------------------------
\n" ); document.write( "Plug (1) into (2)
\n" ); document.write( "(2) $\"+7s+=+%28+s+%2B+27+%29%2A4+\"$
\n" ); document.write( "(2) $\"+7s+=+4s+%2B+108+\"$
\n" ); document.write( "(2) $\"+3s+=+108+\"$
\n" ); document.write( "(2) $\"+s+=+36+\"$
\n" ); document.write( "and
\n" ); document.write( " $\"+s+%2B+27+=+63+\"$
\n" ); document.write( "----------------------
\n" ); document.write( "(1) $\"+d+=+s%2A7+\"$
\n" ); document.write( "(1) $\"+d+=+36%2A7+\"$
\n" ); document.write( "(1) $\"+d+=+252+\"$
\n" ); document.write( "Boris lives 252 mi from the mountains
\n" ); document.write( "---------------------
\n" ); document.write( "check answer:
\n" ); document.write( "(2) $\"+d+=+%28+s+%2B+27+%29%2A4+\"$
\n" ); document.write( "(2) $\"+d+=+63%2A4+\"$
\n" ); document.write( "(2) $\"+d+=+252+\"$
\n" ); document.write( "OK \n" ); document.write( "

\n" );