Two people could fit new windows in a house in 3 days.

• (I) One of the persons fell ill before the work started. How long would the job take now?
• (II) How many people would be needed to fit the windows in 1 day?

To solve the problem, let's break it down into two parts.

Part I: Time Required with One Person

If two people can complete the job in 3 days, their combined work rate is:

• 1 job in 3 days = 1/3 job per day (for two people).

Thus, the work rate for one person is half of that:

• 1/3 job per day ÷ 2 = 1/6 job per day (for one person).

Now, if only one person is working, the total time to complete the job would be:

• 1 job ÷ 1/6 job per day = 6 days.

So, it would take 6 days for one person to fit the windows.

Part II: Number of People Needed for One Day

To finish the job in just 1 day, we need to determine how many people are required to achieve the work rate of 1 job per day.

• Each person works at a rate of 1/6 job per day.
• If we let x be the number of people needed, then:
• x * (1/6) job per day = 1 job per day.

Solving for x gives:

• x = 1 job per day ÷ (1/6 job per day) = 6 people.

Therefore, 6 people would be needed to fit the windows in 1 day.