On which day of the week did 1 October 1994 fall according to the Gregorian calendar?

Introduction / Context:
Finding the day of the week for a specific date, such as 1 October 1994, is a very common calendar aptitude question. It checks whether you understand how days move forward through months and years, how to count odd days, and how to handle month lengths correctly. In exams, you are expected to apply a systematic method instead of guessing the day.

Given Data / Assumptions:

• Date in question: 1 October 1994.
• We assume the standard Gregorian calendar.
• We will use the known reference that 1 January 1994 was a Saturday.
• All months follow their usual lengths: January 31, February 28 in 1994, March 31, April 30, May 31, June 30, July 31, August 31, September 30.

Concept / Approach:
The key concept is odd days. An odd day is the remainder when the total number of days is divided by 7. If you know the day of the week on a reference date, you can reach another date in the same year by counting how many days lie between them and then taking modulo 7. Moving forward by 0 odd days keeps the day same, 1 odd day moves it by one weekday, and so on.

Step-by-Step Solution:
Step 1: Note that 1 January 1994 is taken as Saturday. Step 2: Count days from 1 January to 1 October 1994, month wise. Step 3: January 31, February 28, March 31, April 30, May 31, June 30, July 31, August 31, September 30. Total = 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 = 273 days. Step 4: Find odd days: 273 / 7 gives a remainder of 0, because 273 = 7 * 39. Step 5: Zero odd days means the weekday on 1 October 1994 is the same as on 1 January 1994, that is Saturday.

Verification / Alternative check:
You can verify the result by using a standard day of week algorithm such as Zeller type formulas or by comparing with any reliable perpetual calendar. All correct methods will show that 1 October 1994 is a Saturday. The internal consistency of the month wise counting and the fact that total odd days are zero support the answer.

Why Other Options Are Wrong:
Sunday: This would require one odd day more than Saturday, which is not supported by the count of 273 days giving zero odd days.
Friday: This would require six odd days fewer than Saturday, not matching the calculation.
Wednesday: This is further away and does not correspond to any valid odd day count starting from Saturday with the given month lengths.

Common Pitfalls:
Students often forget to treat February correctly or miscount the total days between two dates. Another mistake is to start counting from 1 January but include 1 October itself as an extra day. Only the days between the reference date and the target date matter. Also, you must always reduce the total days modulo 7 to find the effective shift in weekday.

Final Answer:
Therefore, the day of the week on 1 October 1994 is Saturday.