UPSC Prelims 2016 CSAT Paper II · Q61 of 79 Logical Reasoning medium

A military code writes SYSTEM as SYSMET and NEARER as AENRER. Using the same code, FRACTION can be written as :

  1. (a) CARFTION
  2. (b) FRACNOIT
  3. (c) NOITCARF
  4. (d) CARFNOIT ✓ UPSC's answer

Why the answer is (d)

• The code splits the word into two halves and reverses the order of letters within each half.

• For SYSTEM (6 letters), the first half SY becomes YS and the second half TEM becomes MET, resulting in SYSMET.

• For NEARER (6 letters), the first half NE becomes EN and the second half ARER becomes RERA, resulting in AENRER.

• Applying this to FRACTION (8 letters), split it into FRAC and TION.

• Reverse the first half FRAC to get CARF.

• Reverse the second half TION to get NOIT.

• Combining these gives CARFNOIT, which matches option (d).

Why the other options are wrong

(a) CARFTION
CARFTION only reverses the first half (FRAC to CARF) but leaves the second half (TION) unchanged.
(b) FRACNOIT
FRACNOIT leaves the first half (FRAC) unchanged and only reverses the second half (TION to NOIT).
(c) NOITCARF
NOITCARF reverses the entire word as a single unit rather than reversing each half separately.

Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2016, held on 7 August 2016. 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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