Logical Reasoning, Analytical Ability and Mental Ability (CSAT)
What is tested
Series, syllogisms, blood relations, seating arrangement, coding-decoding, data interpretation and basic numeracy, usually with a qualifying band.
Core methods
- Syllogism: draw the minimum possible Venn diagram, then test whether the conclusion holds in every diagram. "Some A are B" does not imply "Some B are not A".
- Series: check differences first, then ratios, then squares and cubes, then alternating patterns.
- Seating: fix the most constrained person first and draw the arrangement before reading the next clue.
- Blood relations: convert each sentence into a symbol chain rather than relying on a mental picture.
Worked example
Statements: All engineers are graduates. Some graduates are managers. Conclusions: (I) Some engineers are managers. (II) Some managers are graduates. Reasoning: draw graduates as the larger circle containing engineers; the manager circle overlaps graduates, but that overlap may fall entirely outside the engineer circle. So conclusion I is not necessarily true. Conclusion II is a direct restatement of "some graduates are managers", so it follows. Answer: only II follows.
Traps that cost marks
- Assuming the converse of "all A are B".
- Solving a seating puzzle from memory instead of drawing the layout.
- Overrunning on a single item and losing marks elsewhere that are equally weighted.