Reasoning and Mental Ability
Reasoning and Mental Ability is the most scoring section of the paper because the patterns repeat and can be drilled to automaticity.
Question families
- Series: number, letter and mixed.
- Coding–decoding: letter shift, reversal, substitution.
- Blood relations and direction sense.
- Syllogism solved with Venn diagrams.
- Analogy, odd-one-out, ranking and seating arrangement.
Core tools
- Alphabet positions A=1 to Z=26; remember EJOTY (E=5, J=10, O=15, T=20, Y=25); reverse value = 27 − position.
- Series: test differences first, then ratios, then squares and cubes, then alternating sub-series.
- Direction: draw axes and treat left and right as relative to the direction being faced.
- Syllogism: draw the smallest diagram satisfying the statements; a conclusion is valid only if true in every possible diagram.
Worked example
Series: 2, 6, 12, 20, 30, ? Reasoning: the differences are 4, 6, 8, 10 - consecutive even numbers - so the next difference is 12 and the answer is 42. Cross-check with the pattern n(n+1): 1×2, 2×3, 3×4, 4×5, 5×6, so the next term is 6×7 = 42. Both routes agree.
Traps
- Forcing a simple addition pattern when the series actually alternates between two sub-series.
- Mishandling "my father's only son" in blood-relation chains.
- Marking a syllogism conclusion because it seems probable; validity is logical, not probabilistic.
- Forgetting that a person facing south has east on the left.