UPSC Prelims 2017 · CSAT
Question 11: Logical Reasoning and Mental Ability
If second and fourth Saturdays and all the Sundays are taken as only holidays for an office, what would be the minimum number of possible working days of any month of any year?
AnswerUPSC’s answer is (b).
Holidays are every Sunday plus the 2nd and 4th Saturdays, so working days are fewest in the month with the most holidays. A 31-day month has at most 5 Sundays and 2 holiday Saturdays: 31 - 7 = 24. A 30-day month gives 30 - 7 = 23. February has 28 days with 4 Sundays: 28 - 6 = 22, and a leap February with 5 Sundays gives 29 - 7 = 22. The minimum is 22.
Why each option is right or wrong
- (a) 23 is the minimum only for a 30-day month; February gives fewer working days.
- (b) Correct: February has 6 holidays in 28 days (22 working), or 7 in a 29-day leap year (22 working).
- (c) 21 would need more holidays than any month can have.
- (d) 20 is lower still and impossible for the same reason.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2017, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.