General Aptitude: Quantitative Reasoning, Data Interpretation and Verbal Ability
General Aptitude carries 15 marks in GATE ES, with numerical reasoning, data interpretation, logical reasoning and verbal ability. The mathematics is school-level; the difficulty lies in speed, precision and careful reading of the question stem.
Core rules and concepts
- Percentages and ratios: successive changes multiply, not add; percentage points versus percent change; reverse percentages after a discount.
- Averages and mixtures: weighted mean; alligation for mixing two concentrations; mean-speed for equal distances is the harmonic mean.
- Time, speed, distance and work: relative speed for trains; work-rate reciprocals; pipes and cisterns follow the same logic.
- Counting and probability: permutations versus combinations; at least one case computed as 1 minus none.
- Data interpretation: read axes, units and legends before calculating; approximate to eliminate options.
- Reasoning and verbal: syllogisms, seating, blood relations, series; reading comprehension relies on stated content, not outside knowledge.
Worked example
A price rises 20% and then falls 20%. Net multiplier = 1.20 x 0.80 = 0.96, so the final price is 4% below the original, not unchanged. If the original price was Rs 500, the final price is Rs 480, a decrease of Rs 20. The reasoning step is that the second percentage applies to the increased base, not the original. This is the most frequently tested trap in percentage questions.
Traps that cost marks
Adding successive percentages arithmetically; confusing percent with percentage points; using the arithmetic mean for speeds over equal distances; ignoring units in data tables; and choosing an option before checking whether the question asks for the value or the change.