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How long does it take for Sydney to clean the house?

 

 Jul 31, 2020
 #1
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+1

1 / M   +  1/ S  = 1/3

1/5     + 1/S   = 1/3      solve for S   the time alone for Sydney to clean the house

 

 

 

 

Another way (when you have TWO people)

 

S * M / (S+M) = 3

5S = 3S + 15

2S = 15

s = 7.5 hr

 Jul 31, 2020
edited by ElectricPavlov  Jul 31, 2020

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