<PRE><B>Question 762709</B>
Principle 1: Time taken to complete a task is inversely proportional to number of workers. i.e. more workers, less time to complete the same job.

12 workers take 30 days to build the house.

So 1 worker would take 12 times as long to build the house, or (12*30) days.

So 18 workers would take 1/18th the time or {{{12*30/18 = 20}} days.


18 workers can build the house in {{{highlight(20)}}} days.

:)

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