CSS GSA — Paper 7, Part-II, Section VI (Quantitative Ability/Reasoning)

Overlaps heavily with the dedicated CSS Math / General Ability — Index page (under MPT — Quantitative / Math), which holds the full formulas, worked examples, and drills. This page gives the GSA-Paper-7-specific overview and exam angle only.

Basic Mathematical Skills — Core Areas Tested

• Arithmetic:
  • Average: sum of values ÷ number of values
  • Ratios: comparison of two quantities (a:b); Rates: a ratio comparing different units (e.g., speed = distance/time)
  • Percentage: a fraction expressed out of 100; conversions between fraction ↔ decimal ↔ percentage are a common quick-question format
  • Remainders: value left over after division; modular arithmetic questions are common in reasoning-adjacent quant sets
  • Rounding of Numbers: rounding to nearest whole number/decimal place/significant figure — watch for "round half up" vs "round half to even" conventions in tricky questions
• Algebra: linear/quadratic equations, solving for unknowns, Symbols (custom-defined operators — e.g., "if a☆b = a² − b, find 3☆2" — tests rule application over memorized formulas), inequalities
• Geometry:
  • Angles: complementary (sum to 90°), supplementary (sum to 180°), angles on a straight line, around a point (360°)
  • Triangles: angle sum = 180°; types (equilateral, isosceles, scalene, right-angled); Pythagorean theorem (a² + b² = c²) for right triangles
  • Sets: union, intersection, complement, subset relationships; Venn diagrams for visualizing set operations
  • Equations: forming and solving equations from word problems — a frequently tested applied-skill format
• Random Sampling: a method of selecting a subset from a population such that every member has an equal/known chance of selection — foundational statistical concept; contrasted with non-random/biased sampling methods (convenience, judgment sampling)

Exam Angle

• CSS quant questions in GSA are typically applied word problems, not abstract proofs — practice translating a sentence into an equation quickly
• Time management matters more than depth here: most questions are solvable in under a minute once the underlying formula/technique is recognized

Self-Test Questions

1. What is the difference between a ratio and a rate?
2. Solve: if a☆b is defined as a² − b, what is 4☆5?
3. A shop marks up an item by 20% then offers a 10% discount — what is the net percentage change on the original price?
4. State the Pythagorean theorem and use it to find the hypotenuse of a right triangle with legs 6 and 8.