Logical reasoning is the CSAT block that rewards method more than speed. Most questions look unfamiliar the first time and routine the tenth time, because UPSC draws on a small set of patterns: syllogisms, “if–then” statements, assumptions and conclusions, arrangements, relations, directions and sequences. None of them needs more than Class X arithmetic; all of them need a clean diagram.

This chapter is Prelims-only. In CSAT (qualifying at 33%, with one-third negative marking), reasoning questions are a good source of near-certain marks once the method is drilled — and a dangerous time sink if attempted without one.

What this chapter covers

Family	Question types	Topic page
Verbal and analytical logic	Syllogisms, if–then logic, necessary vs sufficient, assumptions, conclusions, courses of action, strengthen/weaken	Syllogisms and Arguments
Puzzles and arrangements	Linear and circular seating, blood relations, directions, ranking, coding–decoding, series, clocks, calendars	Puzzles and Arrangements

Revise with the quick-revision sheet and test yourself on the practice set.