If 10 men can complete the work in 5 days, then we can find the total amount of work done in "man-days" as follows:

$\text{Total work} = 10 \text{ men} \times 5 \text{ days} = 50 \text{ man-days}$

Now, if 3 men are assigned the same work, we can find the number of days required by dividing the total work by the number of men:

$\text{Days required} = \frac{50 \text{ man-days}}{3 \text{ men}} = \frac{50}{3} \approx 16.67 \text{ days}$

Therefore, it would take approximately 16.67 days (or 16 days and 8 hours) for 3 men to complete the same work.

Would you like a detailed breakdown of the calculations or have any questions?

Here are five related questions you might find interesting:

1. What if 15 men were assigned to complete the work? How long would it take?
2. How many men are needed to complete the work in 3 days?
3. If the work needs to be completed in 8 days, how many men would be required?
4. What if each man’s work capacity reduces over time, how would it affect the number of days?
5. How would the calculation change if the work increases by 50%?

Tip: "Man-days" is a useful way to calculate work for varying numbers of workers and time. It helps you scale work requirements easily based on workforce size.