Reasoning, Mental Ability
This section covers series, coding-decoding, blood relations, direction sense, syllogism, seating arrangement, inequalities and non-verbal reasoning. Speed comes from recognising the pattern type within the first two or three terms.
Core tools
Letter positions run A=1 to Z=26; the reverse position is 27 minus the forward position. In blood relations, draw a family tree and mark gender before answering; "only son of my mother" can be the speaker himself. In direction questions, sketch north upwards and apply Pythagoras for the shortest distance. In syllogism, "all A are B" is not reversible, while "some A are B" is; "some A are not B" is not the same as "no A is B". In circular seating, left and right swap when people face outward.
Worked example
Find the next term: 3, 8, 15, 24, 35, ? Differences are 5, 7, 9, 11 - consecutive odd numbers - so the next difference is 13 and the answer is 48. Verify by a second rule: the terms are 2²−1, 3²−1, 4²−1, 5²−1, 6²−1, so the next is 7²−1 = 48. Two independent rules agreeing confirms the answer.
Traps
Reversing left and right in outward-facing seating; assuming a gender that the statement does not give; in inequalities, treating "≥" as ">" and missing the "either-or" pair; in coding, forgetting that the shift may alternate between +1 and −1; in non-verbal questions, counting lines instead of comparing rotation and reflection.