Reasoning Ability
The backbone of the section
Reasoning Ability is pattern recognition plus disciplined deduction. High-yield topics are puzzles and seating arrangement (linear, circular, floor, box, month/day scheduling), syllogism, inequality, coding–decoding, blood relations, direction sense, alphanumeric series, order and ranking, input–output, and data sufficiency.
Approach puzzles by drawing a skeleton first and fixing the most definite clue - a fixed seat, a named floor or a directly stated pair. Keep a two-way table for 'either–or' attributes such as gender, city or colour. For syllogism, draw the minimal Venn diagram that satisfies the statements and never import real-world knowledge. For blood relations, draw a small family tree with symbols for male, female and spouse rather than trying to hold it in your head.
Traps: confusing 'possibility' cases with definite conclusions; reversing left and right when people face inward versus outward; treating every 'either–or' pair as valid; assuming a person's gender from a name; and in inequalities, reading '≥' as strict '>'. In data sufficiency, test each statement alone before combining them.
Worked example: Statements - 'Some pens are books' and 'All books are red.' The conclusion 'Some pens are red' follows necessarily, because the pens that are books must be red. 'All pens are red' does not follow, since some pens may not be books. 'Some books are pens' does follow, because the converse of a 'some' statement is always valid. Rule of thumb: 'some' converts, 'all' does not - from 'All A are B' you may only infer 'Some B are A'.