On 1 December 1991, it is a Tuesday. Which date is the fourth Thursday of December 1991?

Introduction / Context:
This question focuses on counting specific weekdays within a month. Such problems are common in calendar aptitude, where you must determine the date of the nth occurrence of a given weekday in a particular month.

Given Data / Assumptions:

• 1 December 1991 is a Tuesday.
• We must find the date of the fourth Thursday of December 1991.
• We assume the usual 7-day weekday cycle.

Concept / Approach:
Starting from the known weekday for the 1st of the month, we list out the weekdays for the first few days. Once we identify the first Thursday, each subsequent Thursday will occur exactly 7 days apart. Counting these gives us the date of the fourth Thursday in the month.

Step-by-Step Solution:
Step 1: 1 December 1991 is Tuesday (given).Step 2: Therefore, 2 December is Wednesday, 3 December is Thursday, 4 December is Friday, and so on.Step 3: The first Thursday in December 1991 is on 3 December.Step 4: Subsequent Thursdays occur every 7 days: second Thursday is 3 + 7 = 10 December, third Thursday is 10 + 7 = 17 December, and fourth Thursday is 17 + 7 = 24 December.Step 5: Therefore, the fourth Thursday of December 1991 falls on 24 December 1991.

Verification / Alternative check:
You can quickly verify by listing all Thursdays in December 1991 if starting from 1 December as Tuesday: 3rd (Thu), 10th (Thu), 17th (Thu), 24th (Thu), and 31st (Tue + 30 days = Thursday). The fourth one in this sequence is clearly on the 24th, confirming our calculation.

Why Other Options Are Wrong:
22 December and 23 December 1991 are not Thursdays in this setup; they belong to other weekdays in that week. 25 December 1991 is the day after the fourth Thursday and would be a Wednesday or Friday only under a different starting assumption, not matching the given data. 29 December 1991 lies even later in the month and is certainly not the fourth Thursday when counting from the 3rd, 10th and 17th.

Common Pitfalls:

• Miscounting the first Thursday, for example starting from 1 December instead of moving correctly from Tuesday to Thursday.
• Adding incorrect intervals (e.g., 5 or 6 days) instead of the fixed 7-day gap between occurrences of the same weekday.
• Stopping at the third Thursday or overshooting to the fifth without carefully counting the sequence.

Final Answer:
The fourth Thursday of December 1991 was on 24 December 1991.