document.write( "Question 1023723: You drive at an average speed of 50mph to a discount shopping mall, spend two hours shopping, and then return at an average speed of 25mph. The entire trip take 8 hours. How far away is the shopping mall? \n" ); document.write( "

Algebra.Com's Answer #639233 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Time spent shopping is not travel time, so
\n" ); document.write( " $\"+8+-+2+=+6+\"$ hrs travel time
\n" ); document.write( "Let $\"+d+\"$ = distance to shopping mall
\n" ); document.write( "Let $\"+t+\"$ = time in hrs to get to shopping mall
\n" ); document.write( " $\"+6+-+t+\"$ = time in hrs to back from shopping mall
\n" ); document.write( "-----------------------------------------
\n" ); document.write( "Going to the mall:
\n" ); document.write( "(1) $\"+d+=+50t+\"$
\n" ); document.write( "Coming back from the mall:
\n" ); document.write( "(2) $\"+d+=+25%2A%28+6+-+t+%29+\"$
\n" ); document.write( "-------------------------
\n" ); document.write( "By substitution:
\n" ); document.write( "(2) $\"+50t+=+25%2A%28+6+-+t+%29+\"$
\n" ); document.write( "(2) $\"+50t+=+150+-+25t+\"$
\n" ); document.write( "(2) $\"+75t+=+150+\"$
\n" ); document.write( "(2) $\"+t+=+2+\"$
\n" ); document.write( "Plug this result back into (1) or (2)
\n" ); document.write( "(1) $\"+d+=+50t+\"$
\n" ); document.write( "(1) $\"+d+=+50%2A2+\"$
\n" ); document.write( "(1) $\"+d+=+100+\"$
\n" ); document.write( "The shopping mall is 100 mi away
\n" ); document.write( "-----------------
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+d+=+25%2A%28+6+-+t+%29+\"$
\n" ); document.write( "(2) $\"+d+=+25%2A%28+6+-2+%29+\"$
\n" ); document.write( "(2) $\"+d+=+25%2A4+\"$
\n" ); document.write( "(2) $\"+d+=+100+\"$
\n" ); document.write( "OK \n" ); document.write( "

\n" );