General Aptitude and Reasoning (Quantitative, Logical, Verbal)
General Aptitude and Reasoning tests quantitative speed, logical deduction, and verbal accuracy. The quantitative part is arithmetic and algebra; the logical part includes series, syllogisms, and coding; the verbal part includes grammar and comprehension.
Core rules
- Percentage change uses the original base; successive changes multiply factors, not add percentages.
- Time-speed-distance: convert km/h to m/s by multiplying by 5/18.
- Work problems: combined rate is the sum of individual rates; time is the reciprocal of rate.
- Permutations order matters; combinations do not. Probability P(A) = n(A)/n(S).
- Syllogism conclusions must follow from all premises; some A are B does not imply some B are not A.
- Coding-decoding uses position shifts, reversals, or letter-pair patterns; verify with every given example.
Worked example
A 120 m train travels at 54 km/h and passes a pole. Convert speed: 54 × 5/18 = 15 m/s. Time to pass the pole equals train length divided by speed: 120/15 = 8 s. The reasoning is that passing a pole requires the whole train length to clear a point, unlike passing a platform where platform length is added.
Traps
Adding percentage changes instead of multiplying; using the wrong base in profit and loss; assuming a syllogism's converse; and reading comprehension answers from memory rather than from the passage.