Quantitative Aptitude Cheat Sheet

Key Definitions

• Average: The sum of values divided by the number of values. ✅

• Percentage: A fraction expressed as a part of 100. ✅

• Ratio: A comparison of two quantities by division. ✅

• Proportion: An equation that states two ratios are equal. ✅

Important Concepts

Number Systems

• Natural Numbers: {1, 2, 3, ...} ✅

• Integers: {..., -2, -1, 0, 1, 2, ...} ✅

• Rational Numbers: Numbers that can be expressed as a fraction. ✅

Algebra

• Solving Linear Equations: ax + b = 0 ➔ x = -b/a ✅

• Quadratic Formula: x = (-b ± √(b² - 4ac)) / 2a ✅

Geometry

• Area of Circle: A = πr² ✅

• Pythagorean Theorem: a² + b² = c² ✅

Key Formulas

• Simple Interest: SI = (P × R × T) / 100 ✅

• P: Principal amount

• R: Rate of interest

• T: Time (in years)

• Compound Interest: A = P(1 + r/n)^(nt) ✅

• A: Amount after time

• n: Number of times interest applied per time period

Common Mistakes to Avoid

Common Mistake: Confusing simple interest with compound interest calculations.

Common Mistake: Forgetting to convert percentages to decimals in calculations.

Memory Tricks

Tip: "PEMDAS" — Parentheses, Exponents, Multiplication and Division (from left to right), Addition and Subtraction (from left to right).

Key Diagrams

       +---------+
       |         |
       | Circle  |
       |         |
       +---------+
          Area = πr²
           Triangle
          /|
         / |
        /  | Height
       /   |
      ------
        Base