In a month of 31 days that begins on a Friday, the second and fourth Saturdays and every Sunday are holidays. How many working days are there in that month?

Introduction / Context:
This is a classic calendar aptitude question that checks whether you can track days of the week across a month and correctly count working days when specific weekends are declared holidays. Such problems are common in banking and government exams, where second and fourth Saturdays plus all Sundays are treated as holidays, just like many Indian offices and banks.

Given Data / Assumptions:

• The month has 31 days.
• The month starts on a Friday (1st is Friday).
• The 2nd and 4th Saturdays are holidays.
• Every Sunday is a holiday.
• All other days are working days.

Concept / Approach:
We first determine the dates on which Saturdays and Sundays fall by moving forward from Friday. From these, we identify which Saturdays are the 2nd and 4th and then count all holiday dates. Finally, we subtract the number of holidays from the total number of days in the month to obtain the total working days.

Step-by-Step Solution:
Step 1: Since the 1st of the month is Friday, the 2nd is Saturday and the 3rd is Sunday.Step 2: Saturdays in the month will therefore be on dates 2, 9, 16, 23 and 30.Step 3: Sundays in the month will fall on dates 3, 10, 17, 24 and 31.Step 4: The second Saturday is on the 9th and the fourth Saturday is on the 23rd. These two Saturdays, plus all Sundays, are holidays.Step 5: List all holiday dates: Saturdays (9, 23) and Sundays (3, 10, 17, 24, 31). This gives a total of 7 holidays.Step 6: Total days in the month = 31. Therefore, working days = 31 − 7 = 24.

Verification / Alternative check:
A quick sanity check is to note that there are 5 Saturdays and 5 Sundays in any 31-day month that begins on a Friday. If only the 2nd and 4th Saturdays are holidays (2 out of 5), then total weekend holidays = 2 Saturdays + 5 Sundays = 7 days. Subtracting these 7 from 31 again gives 24 working days, confirming our detailed count.

Why Other Options Are Wrong:
Option 23 assumes one extra holiday that does not exist. Option 22 assumes two extra holidays. Option 25 and 26 underestimate the number of holidays and overestimate working days. Only 24 matches the correct count of holidays and working days based on the given pattern.

Common Pitfalls:

• Treating all Saturdays as holidays instead of only the second and fourth.
• Miscounting Sundays or forgetting that 31-day months can have 5 Sundays.
• Making an off-by-one error when listing the dates of Saturdays and Sundays.

Final Answer:
The number of working days in the month is 24.