Question Analysis:
The question asks for the day of the week after 126 days from a given starting day. We need to determine the day of the week after this time period.

Given Information:
Starting day: Friday

Solution:
To solve this problem, we need to determine the number of weeks and the remaining days after 126 days. Let's break down the solution into steps:

Step 1: Determine the Number of Weeks
Since there are 7 days in a week, we divide the total number of days (126) by 7 to find the number of weeks. The remainder will be used to determine the final day of the week.

126 ÷ 7 = 18 weeks

Step 2: Determine the Remaining Days
To find the remaining days, we take the remainder of the division in Step 1.

126 mod 7 = 0 remaining days

Since the remainder is 0, there are no remaining days.

Step 3: Determine the Final Day
To determine the final day, we add the number of weeks to the starting day. Since there are 18 weeks, we count 18 days forward from the starting day.

Friday + 18 days = ?

To determine the final day, we need to count the days from Friday:

Friday → Saturday → Sunday → Monday → Tuesday → Wednesday → Thursday → Friday → Saturday → Sunday → Monday → Tuesday → Wednesday → Thursday → Friday → Saturday → Sunday → Monday

After counting 18 days, we reach Monday.

Therefore, the final day after 126 days is Monday.

Conclusion:
After 126 days from a starting day of Friday, the final day will be Monday.