SOLUTION: there are 3 kids in a family . anna ,peter and maria .anna can clean the house fpor 1 hour ,peter can do the same job for 3 hours and maria nees 6 hours .how much time do they nee

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Question 1162637: there are 3 kids in a family . anna ,peter and maria .anna can clean the house fpor 1 hour ,peter can do the same job for 3 hours and maria nees 6 hours .how much time do they need to work to finish the same cleaning if they do it altogether?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Their combined speed is 1%2F1%2B1%2F3%2B1%2F6=6%2F6%2B2%2F6%2B1%2F6=9%2F6=3%2F2 jobs%2Fhours.

Reciprocal of that is 2%2F3 HOURS for ONE JOB; or in this example, 40 minutes.