Question 362289
linda can do the job by herself in 6 hours. 
If Laura helps, they get the job done in 5 1/2 hours. 
 
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linda can do 1/6 of the job in 1 hour.
together they can do 2/11 of the job in 1 hour
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2/11-1/6 
LCM =66
(12-11)/20
1/20 of the job
so Laura can do the job in 20 hours alone
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m.ananth@hotmail.ca