Reasoning and Quantitative Aptitude
Reasoning and Quantitative Aptitude tests pattern recognition and logical deduction rather than syllabus knowledge: number and letter series, analogies, coding-decoding, blood relations, direction sense, syllogism, seating arrangement, ranking, and simple data interpretation.
Core rules
- Series: check differences first, then ratios, then alternating, square or cube patterns. For letters, convert to positions (A = 1 ... Z = 26).
- Coding-decoding: compare one word with its code to find the shift or reversal rule, then apply it to the target word.
- Blood relations: draw a family tree; mark gender and use vertical lines for parent-child, horizontal for spouse.
- Direction sense: fix a compass, then track net displacement; use Pythagoras when turns are at right angles.
- Syllogism: draw Venn diagrams; a conclusion is valid only if it holds in every possible diagram.
- Seating: draw the row or circle and mark facing direction before placing anyone.
Worked example
Series: 3, 8, 15, 24, 35, ?. The differences are 5, 7, 9, 11 - consecutive odd numbers. The next difference is 13, so the answer is 35 + 13 = 48. Equivalently, the terms are n² − 1 for n = 2, 3, 4, 5, 6, 7.
Traps that cost marks
- Reading a 'not true' question as a positive one.
- Taking left and right from the reader's view instead of the person's facing direction.
- In syllogism, treating a 'possibility' conclusion as definite.
- In blood relations, missing that 'my father's only son' may be the speaker himself.
- Misreading units or the year column in data interpretation.