a) 30 days
b) 40 days
c) 50 days
d) 60 days
Correct Answer is:
b) 40 days
Explanation
![20 persons can finish a work in 30 days working 18 hours per day 20 persons can finish a work in 30 days working 18 hours per day](https://sciencesparkle.com/wp-content/uploads/2024/04/25-2-1024x176.png)
Here,
Person and Hours are inversely proportional to Days.
\therefore x=30\times\large\frac{20}{30}\normalsize\times\large\frac{18}{9}
\rightarrow x=40 days
Ans: It will take 30 persons a total of 40 days to finish the work if they each work for 9 hours per day.