1. The problem asks: How many persons are needed to fit the window in a day? 2. To solve this, we need more information such as the total work required, the work rate of one person, or the time taken by one person to fit the window. 3. The general formula for work problems is: $$\text{Work} = \text{Rate} \times \text{Time}$$ 4. If one person can fit the window in $t$ days, then the rate of one person is $\frac{1}{t}$ windows per day. 5. If $n$ persons work together, their combined rate is $n \times \frac{1}{t} = \frac{n}{t}$ windows per day. 6. To complete 1 window in 1 day, we set the combined rate equal to 1: $$\frac{n}{t} = 1$$ 7. Solving for $n$ gives: $$n = t$$ 8. Therefore, the number of persons needed to fit the window in one day is equal to the number of days it takes one person to do the job alone. Please provide the time it takes for one person to fit the window so we can calculate the exact number of persons needed.