UPSC Prelims 2018 CSAT Paper II · Q59 of 58 Mental Ability medium

Consider the sequence given below : 4/12/95, 1/1/96, 29/1/96, 26/2/96, .... What is the next term of the series?

  1. (a) 24/3/96
  2. (b) 25/3/96 ✓ UPSC's answer
  3. (c) 26/3/96
  4. (d) 27/3/96

Why the answer is (b)

• The sequence represents dates in DD/MM/YY format: 4/12/95, 1/1/96, 29/1/96, 26/2/96.

• Calculate the number of days between consecutive terms: From 4/12/95 to 1/1/96 is 28 days (27 days remaining in Dec 95 + 1 day in Jan 96).

• From 1/1/96 to 29/1/96 is 28 days.

• From 29/1/96 to 26/2/96 is 28 days (2 days remaining in Jan 96 + 26 days in Feb 96).

• The pattern is an addition of 28 days to the previous date.

• Adding 28 days to 26/2/96: February 1996 has 29 days (leap year), so 3 days remain in Feb (27, 28, 29). 28 - 3 = 25 days into March. Thus, the next date is 25/3/96.

Why the other options are wrong

(a) 24/3/96
24/3/96 is 27 days after 26/2/96, which breaks the consistent 28-day interval pattern.
(c) 26/3/96
26/3/96 is 29 days after 26/2/96, which breaks the consistent 28-day interval pattern.
(d) 27/3/96
27/3/96 is 30 days after 26/2/96, which breaks the consistent 28-day interval pattern.

Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2018, held on 3 June 2018. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.

Reading the answer is not the same as getting it right under a clock. Practise this question with UPSC's negative marking, and anything you miss goes into an error notebook until you get it right twice.

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