document.write( "Question 1079833: If it took Billy an hour to race over to his girlfriend’s house but two hours if he went 20 mph slower, how far away does Billy’s girlfriend live? \n" ); document.write( "

Algebra.Com's Answer #694063 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+d+\"$ = the distance to his girlfriend's house
\n" ); document.write( "Let $\"+s+\"$ = his running speed in mi/hr
\n" ); document.write( "(1) $\"+d+=+s%2A1+\"$
\n" ); document.write( "(2) $\"+d+=+%28+s-20+%29%2A2+\"$
\n" ); document.write( "-----------------------
\n" ); document.write( "Plug (1) into (2)
\n" ); document.write( "(2) $\"+s+=+%28+s-20+%29%2A2+\"$
\n" ); document.write( "(2) $\"+s+=+2s+-+40+\"$
\n" ); document.write( "(2) $\"+s+=+40+\"$
\n" ); document.write( "-----------------------
\n" ); document.write( "Plug this result into (1)
\n" ); document.write( "(1) $\"+d+=+40%2A1+\"$
\n" ); document.write( "(1) $\"+d+=+40+\"$
\n" ); document.write( "His girlfriend lives 40 mi away
\n" ); document.write( "----------------------------
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+d+=+%28+s-20+%29%2A2+\"$
\n" ); document.write( "(2) $\"+d+=+%28+40-20+%29%2A2+\"$
\n" ); document.write( "(2) $\"+d+=+20%2A2+\"$
\n" ); document.write( "(2) $\"+d+=+40+\"$ mi
\n" ); document.write( "OK \n" ); document.write( "

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