If 17 March 1997 falls on a Monday, what day of the week was 17 March 1996?

Introduction / Context:
This question examines your ability to move backward in time on the calendar and account for leap years correctly. Moving from a known date in one year to the same date in the previous year requires you to consider whether the earlier year is a leap year and whether February 29 lies in the interval between the two dates.

Given Data / Assumptions:

• 17 March 1997 is a Monday.
• We must find the weekday for 17 March 1996.
• We are using the Gregorian calendar.
• We need to check whether 1996 is a leap year.

Concept / Approach:
To move from 17 March 1997 back to 17 March 1996, consider the length of the year 1996. If the earlier year (1996) is a leap year and the date considered (17 March) lies after 29 February, then the difference between the two dates is 366 days, which shifts the weekday by 2 days (since 366 mod 7 = 2). If it were a non-leap year, the difference would be 365 days, shifting the weekday by 1 day.

Step-by-Step Solution:
Step 1: Check whether 1996 is a leap year. 1996 is divisible by 4 and is not a century year, so it is a leap year.Step 2: The period from 17 March 1996 to 17 March 1997 includes the extra day 29 February 1996.Step 3: Therefore, the number of days between 17 March 1996 and 17 March 1997 is 366 days.Step 4: Compute 366 mod 7. Since 7 * 52 = 364, the remainder is 2 days.Step 5: This means that the weekday advances by 2 days when moving from 17 March 1996 to 17 March 1997.Step 6: We know 17 March 1997 is Monday. Moving backward 2 days gives: Monday → Sunday (1 day back) → Saturday (2 days back).Step 7: Therefore, 17 March 1996 was a Saturday.

Verification / Alternative check:
We can also move forward instead: if 17 March 1996 were Saturday and we move forward 366 days (a leap year), the weekday shifts by +2, so Saturday → Sunday (+1) → Monday (+2), which matches the given information for 1997. This confirms our backward calculation.

Why Other Options Are Wrong:
Monday would imply no shift, Tuesday a +1 shift, Wednesday a +2 shift in the wrong direction, and Sunday a +1 shift backward instead of 2. Only Saturday produces the correct 2-day difference consistent with a leap year between the two dates.

Common Pitfalls:

• Forgetting that 1996 is a leap year and treating the difference as 365 days instead of 366.
• Moving in the wrong direction (forward instead of backward) without reversing the day-of-week adjustment.
• Miscounting the two-day shift when converting between dates across a leap year.

Final Answer:
The day of the week on 17 March 1996 was Saturday.