UPSC Prelims 2026 · CSAT Paper 2 · Set DLogical ReasoningQ 78 / 80

UPSC Prelims 2026 CSAT Paper 2 — Question 78

Question

A pattern formed by two characters a and b is repeated more than once in the following string (□ marks an unknown position): □ b □ a □ a □ □ a □ a □ b a b What is □□ in the 7th and 8th positions from the left in the above string?

(a)aa
(b)ab
(c)ba
(d)bb

UnlockIAS answer: (d)bb

Solution

Filling the blanks so that a fixed two-character block repeats consistently across the string, the 7th and 8th positions must both be b — i.e. "bb".

UnlockIAS expert key, prepared 24 May 2026 and cross-verified by re-deriving the answer — this is our key, not the official UPSC provisional key (awaited).

Section

Logical Reasoning

Topic Reference

Logical Reasoning — Pattern in a string

Official UPSC key still awaited

UPSC has announced (PIB Release 2262441, 18 May 2026) that the provisional answer key for CSE Prelims 2026 will be released “soon after Exam”. Until then, use the CSAT score calculator for your qualifying-status estimate, and join the per-question discussion below.

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Official Notification

PIB Release 2262441

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