document.write( "Question 319389: if 'a' can do a job in 4hrs and 'b' can do it in 6hrs, how long will it take if both do it together. and the eqaution to figure it out. ty \n" ); document.write( "

Algebra.Com's Answer #228710 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Add their rates working separately to get
\n" ); document.write( "theirs rates working together
\n" ); document.write( "In words:
\n" ); document.write( "(1 job/a's time) + (1 job/b's time) = 1 job/working together
\n" ); document.write( " $\"1%2F4+%2B+1%2F6++=+1%2Fx\"$
\n" ); document.write( "multiply both sides by $\"12x\"$
\n" ); document.write( " $\"3x+%2B+2x++=+12\"$
\n" ); document.write( " $\"5x+=+12\"$
\n" ); document.write( " $\"x+=+12%2F5\"$
\n" ); document.write( "Working together, they can do the job in 2.4 hrs \n" ); document.write( "

\n" );