document.write( "Question 292396: Cleaning service number 1 can clean a certain office building in 30 hours, while the cleaning service number 2 can clean the same building in 20 hours. If the two companies work together, how long would it take to clean the building? \n" ); document.write( "
Algebra.Com's Answer #211225 by richwmiller(17219)\"\" \"About 
You can put this solution on YOUR website!
This is indeed a word problem. How did you decide that it is travel and distance word problem?
\n" ); document.write( "x/30+x/20=1
\n" ); document.write( "2x+3x=60
\n" ); document.write( "5x=60
\n" ); document.write( "x=12
\n" ); document.write( "Together the two companies can do the job in 12 hours.
\n" ); document.write( "check
\n" ); document.write( "12/30+12/20=1
\n" ); document.write( "2/5+3/5=1
\n" ); document.write( "ok\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
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