document.write( "Question 854011: I need help. I am having trouble setting up the equation.\r
\n" ); document.write( "\n" ); document.write( "A cyclist rides a distance of 100 miles to a distant city. His return trip takes 3 hours longer because his speed decreases by 30 mph. How fast did he ride each way?
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Algebra.Com's Answer #514410 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
Let \"+s+\" = his speed riding to the city
\n" ); document.write( "\"+s-30+\" = his speed returning
\n" ); document.write( "Let \"+t+\" = his time in hours to get to the city
\n" ); document.write( "\"+t+%2B+3+\" = his time returning
\n" ); document.write( "---------------------------------
\n" ); document.write( "Equation for 1st trip:
\n" ); document.write( "(1) \"+100+=+s%2At+\"
\n" ); document.write( "Equation for return trip
\n" ); document.write( "(2) \"+100+=+%28+s+-+30+%29%2A%28+t+%2B+3+%29+\"
\n" ); document.write( "-----------------------------
\n" ); document.write( "(2) \"+100+=+s%2At+-+30t+%2B+3s+-+90+\"
\n" ); document.write( "(2) \"+100+=+%28+t+%2B+3+%29%2As+-+30t+-+90+\"
\n" ); document.write( "(2) \"+%28+t+%2B+3+%29%2As+=+30t+%2B+190+\"
\n" ); document.write( "(2) \"+s+=+%28+30t+%2B+190+%29+%2F+%28+t+%2B+3+%29+\"
\n" ); document.write( "Substitute this result into (1)
\n" ); document.write( "------------------------------
\n" ); document.write( "(1) \"+100+=+%28+t%2A%28+30t+%2B+190+%29%29+%2F+%28+t+%2B+3+%29+\"
\n" ); document.write( "(1) \"+100t+%2B+300+=+30t%5E2+%2B+190t+\"
\n" ); document.write( "(1) \"+30t%5E2+%2B+90t+-+300+=+0+\"
\n" ); document.write( "(1) \"+t%5E2+%2B+3t+-+10+=+0+\"
\n" ); document.write( "I can see by looking at it, this is:
\n" ); document.write( "(1) \"+%28+t+%2B+5+%29%2A%28+t+-+2+%29+\"
\n" ); document.write( "\"+t+=+2+\" ( because time is positive, not negative )
\n" ); document.write( "--------------------
\n" ); document.write( "\"+t+=+2+\" hrs is his time to get to the city
\n" ); document.write( "\"+t+%2B+3+=+5+\" hrs is his time to return
\n" ); document.write( "---------------
\n" ); document.write( "check:
\n" ); document.write( "(1) \"+100+=+s%2At+\"
\n" ); document.write( "(1) \"+100+=+s%2A2+\"
\n" ); document.write( "(1) \"+s+=+50+\"
\n" ); document.write( "and
\n" ); document.write( "(2) \"+100+=+%28+s+-+30+%29%2A%28+t+%2B+3+%29+\"
\n" ); document.write( "(2) \"+100+=+%28+s+-+30+%29%2A5+\"
\n" ); document.write( "(2) \"+20+=+s+-+30+\"
\n" ); document.write( "(2) \"+s+=+20+%2B+30+\"
\n" ); document.write( "(2) \"+s+=+50+\"
\n" ); document.write( "OK\r
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