UPSC Prelims 2023 · CSAT
Question 80: Logical Reasoning and Mental Ability
The letters of the word “INCOMPREHENSIBILITIES” are arranged alphabetically in reverse order. How many positions of the letter/letters will remain unchanged ?
AnswerUPSC’s answer is (c).
The word has 21 letters: I five times, E three times, N twice, S twice, and C, O, M, P, R, H, B, L, T once each. In reverse alphabetical order the arrangement is T, S, S, R, P, O, N, N, M, L, I, I, I, I, I, H, E, E, E, C, B. Compare it place by place with INCOMPREHENSIBILITIES: only positions 13 and 15 hold the same letter (I) in both. So two positions stay unchanged.
How you could have got this
No shortcut here: in a “how many” question, ruling out options doesn’t help. Every statement has to be judged.
Which options go is worked out from UPSC’s key and the options, not by a model.
Why each option is right or wrong
- (a) Wrong: positions 13 and 15 both hold I before and after.
- (b) Wrong: two positions match, not one.
- (c) Right: positions 13 and 15 stay as I.
- (d) Wrong: no third position matches.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2023, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.