Question 376183
Nancy and Angelica share in cleaning the house as a part of their training at home. Working alone, Nancy can clean the house in 4 hrs. Working together, it will take them 2 hrs. and 40 min. How long will it take Angelica to do the job working alone? 

Nancy can clean in 4 hours
so she can do 1/4 of the job in 1 hour.
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Together they do the job8 in 2 hr. 40 minutes= 2 2/3 hours = 8/3 hours
so they can do 3/8 of the job in 1 hour
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Angelica alone will do in 3/8 - 1/4 of the job in 1 hour
=(3-2)/8
=1/8  of the job in 1 hour
so she will take 8 hours to do the job
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m.ananth@hotmail.ca