Reasoning and Logical Ability
Question families
Number and alphabet series, coding–decoding, analogies and odd-one-out, syllogism, statement–assumption and statement–conclusion, blood relations, direction sense, linear and circular seating, ranking, and non-verbal items (figure series, mirror and water images, paper folding, embedded figures). Roughly a third is verbal logic, a third puzzles, and a third series plus coding.
Rules that decide answers
- In syllogism, a conclusion follows only if it is true in every diagram consistent with the premises. 'Some A are B' never implies 'All A are B' and does not automatically imply 'Some A are not B'.
- In assumption questions, judge only what the statement necessarily presupposes; outside knowledge is a distractor.
- In direction sense, draw the path and mark left/right after each turn relative to the traveller, not the page.
- In circular seating with people facing the centre, a neighbour to a person's left appears on the reader's right - fix one person first.
Worked example
Series: 3, 8, 15, 24, 35, ? First differences are 5, 7, 9, 11 - an arithmetic progression rising by 2. The next first difference is 13, so the missing term is 35 + 13 = 48. Equivalently the terms are n² − 1 for n = 2, 3, 4, …, and 7² − 1 = 48 confirms it. Always build the difference table before assuming a constant ratio.
Traps that cost marks
- Assuming 'some' means 'some but not all' - the standard convention permits all.
- Reversing relation direction: 'my father's sister's son' is a cousin, not an uncle.
- Continuing an alphabet series without wrapping at Z (A = 1 … Z = 26, then 27 ≡ A).
- Treating a coding rule as positional when it is actually a fixed letter shift.
- Importing real-world facts into statement–conclusion items.