Re: 20 men complete one-third of a piece of work in 20 days. How many more
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24 Jan 2021, 14:15
Work = number of workers * rate * time
So for 20 workers, 20 days with 1/3 of the job done, we solve for the rate. This gives us 1/1200 which represents the amount of work done by ONE man in ONE day. This rate will be the same regardless of the extra men hired.
(2/3) = (x+20) * (1/1200) * (25)
We use 25 for the extra days remaining and 2/3 for the rest of the work left. x represents the extra people needed to be hired on top of the 20 that are already working. From here we solve for x, and see that x=12. Option B.