a) 6 hours per day
b) 4 hours per day
c) 3 hours per day
d) 5 hours per day
correct answer is: a) 6 hours per day
Explanation
Finish a work in 12 days a man working 8 hours per day
\therefore Finish a work in 1 day a man working =\left(8\times12\right) hours per day
\therefore Finish a work in 16 days a man working =\left(\frac{8\times12}{16}\right) hours per day
\rightarrow 6 hours per day.
Ans: 6 hours per day A man will have to work to finish the work.
Another way, Rules of Three Method
![A man working 8 hours per day takes 12 days to finish a work](https://sciencesparkle.com/wp-content/uploads/2024/03/8-hours-per-day-takes-12-days-to-finish-a-work-1024x153.png)
Days and Hours are Inversely Proportional.
\therefore\;16\;:\;12\;:\;:\;8\;:\;x
\rightarrow\large\frac{16}{12}=\frac{8}{x}
\rightarrow 16x=12\times8
\rightarrow x=\large\frac{12\times8}{16}
\rightarrow x=6 hours
Ans: He have to work 6 hours per day.
There’s another way to pose this same math question:
- If a man working 8 hours per day takes 12 days to finish a task, how many hours per day must he work to complete the task in 16 days?
- How many hours per day does a man need to work in order to finish a task in 16 days, if he typically works 8 hours per day and completes it in 12 days?
- Given that a man completes a task in 12 days by working 8 hours per day, how many hours per day should he work to finish the same task in 16 days?
- If a man completes a task in 12 days by working 8 hours per day, how many hours per day does he need to work to finish the same task in 16 days?