Mental Ability and Reasoning: Series Logic, Direction Sketches and Venn Checks
Reasoning rewards a fixed procedure per question type: series, analogy, coding-decoding, blood relations, direction sense, ranking, syllogism, clock and calendar, dice and cubes, mirror and water image, and seating arrangement.
Core rules
- Alphabet positions: A = 1 to Z = 26; EJOTY (E = 5, J = 10, O = 15, T = 20, Y = 25) is a fast anchor; opposite letters sum to 27.
- Direction: sketch every move on one diagram. Facing north, left is west; facing south, left is east.
- Syllogism: test each conclusion on a Venn diagram; possibility conclusions need a two-circle check before rejection.
- Calendar: count odd days; a normal year shifts the weekday by 1, a leap year by 2.
- Clock: the hands coincide every 65 5/11 minutes, not every 65 minutes.
Worked example
Find the next term: 3, 10, 29, 66, ? Reasoning: 3 = 1³ + 2, 10 = 2³ + 2, 29 = 3³ + 2, 66 = 4³ + 2. The pattern is n³ + 2, so the next term is 5³ + 2 = 127.
Traps that cost marks
- Assuming a constant difference when terms are squares, cubes or alternating; check differences first, then ratios, then powers.
- Rushing blood relations: rewrite blood relations step by step rather than leaping to sister or aunt.
- Habitually writing west after a right turn taken while facing south.
- Applying a shift to the whole word instead of position-wise in coding.
Attempt the easy sets first and mark only after eliminating; wild guessing in a negative-marking paper erases the gain from solved questions.