In a 30-day month that begins on a Saturday, all Sundays and every second Saturday (that is, the 2nd and 4th Saturdays) are holidays.\nHow many working days are there in that month?

Introduction / Context:
Calendar-based aptitude questions often ask you to count weekends or specific off days in a given month. Here, you have to work out how many days are actually working days when all Sundays and every second Saturday (2nd and 4th Saturday of the month) are holidays in a 30-day month starting on a Saturday.

Given Data / Assumptions:

The month has exactly 30 days.
Day 1 of the month is a Saturday.
All Sundays are holidays.
Every second Saturday (2nd and 4th Saturdays of the month) is also a holiday.
All other days are working days.

Concept / Approach:
We first lay out the sequence of days of the week for the entire 30-day month. Then we identify which dates are Sundays and which dates are the 2nd and 4th Saturdays. These dates are counted as holidays. Finally, we subtract the total number of holidays from 30 to obtain the total number of working days.

Step-by-Step Solution:
Step 1: List weekdays for the first week. Day 1: Saturday, Day 2: Sunday, Day 3: Monday, Day 4: Tuesday, Day 5: Wednesday, Day 6: Thursday, Day 7: Friday. Step 2: Continue the pattern up to Day 30. Saturdays: Days 1, 8, 15, 22, 29. Sundays: Days 2, 9, 16, 23, 30. Step 3: Identify holiday Saturdays. Every second Saturday means the 2nd and 4th Saturdays, which are Days 8 and 22. Step 4: Count all holidays. Holiday Sundays: 2, 9, 16, 23, 30 (5 days). Holiday Saturdays: 8, 22 (2 days). Total holidays = 5 + 2 = 7 days. Step 5: Compute working days. Working days = 30 - 7 = 23.

Verification / Alternative check:
You can quickly verify by noting there are 4 complete weeks (28 days) plus 2 extra days. In 4 weeks, there are exactly 4 Sundays and 4 Saturdays. With the 30-day pattern, one additional Saturday (Day 29) and one additional Sunday (Day 30) appear, giving 5 Sundays and 5 Saturdays total. Among the Saturdays, only 2 (2nd and 4th) are counted as extra holidays beyond Sundays, giving exactly 7 holidays overall.

Why Other Options Are Wrong:
22 or 24 working days would assume either one fewer or one more holiday than actually present. 25 working days would require only 5 holidays (just Sundays) and ignore the given second-Saturday rule.

Common Pitfalls:
Many learners misinterpret “every second Saturday” as every alternate Saturday starting from the first Saturday, which would change the count. Others forget to include the fifth Sunday that appears when the month starts on a Saturday. Carefully writing out the weekday sequence prevents these errors.

Final Answer:
The month has 23 working days.