Question 967600
Assuming that all the workers are equally efficient, i.e., they each one takes the same amount of time to do a given amount of work,
Time taken by 20 workers to finish the job(T20) = 30 days
Time taken by one worker to finish the job(T1) = T20*30 days = 600 days
Time taken by 15 workers to finish the job(T15) = T1/15 = 40 days