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The Problem

A painter can finish painting a house in 7 hours. Her assistant takes 9 hours to finish the same job. How long would it take for them to complete the job if they were working together?

Answer provided by our tutors

1 hour work of painter   1/7

1 hour work of assistant  1/9

total 1 hour work  = 1/7 + 1/9 = 16/63

so they both complete in

63/16 = 3  15/16    hours

 

 

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