Module 2 · SSC GD Mathematics
Percentage
Percentage change, successive change, profit-loss.
Basic % · Successive Change · Profit-Loss %
Learning Objectives
- Understand the fundamental concepts of Percentage
- Apply key formulas and techniques to solve problems
- Practice with exam-level questions to build speed and accuracy
Key Concepts
Percentage for SSC GD & Agniveer
Percentage means per hundred. Questions on percentage form a significant portion of the mathematics section in SSC GD and Agniveer exams. The topic also forms the basis for profit-loss, simple interest, and data interpretation.
Key Concepts
Basic Formula: Percentage = (Part/Whole)×100. Fraction equivalents: 1/2=50%, 1/3=33.33%, 1/4=25%, 1/5=20%, 1/6=16.67%, 1/8=12.5%, 1/10=10%. Percentage Change: Increase% = (Increase/Original)×100. Decrease% = (Decrease/Original)×100. Successive Percentage: Net change after x% and y% = x + y + (xy/100)%. A 10% increase followed by 10% decrease = 1% net decrease. Population/Depreciation: After n years: P(1+r/100)^n or P(1-r/100)^n.
Solved Examples
Example 1
What is 15% of 300?
a) 40 b) 45 c) 50 d) 55
a) 40 b) 45 c) 50 d) 55
Solution: b) 45. 15% = 15/100 × 300 = 45.
Example 2
A number increased by 20% becomes 240. Find the original number.
a) 180 b) 190 c) 200 d) 220
a) 180 b) 190 c) 200 d) 220
Solution: c) 200. Let number be x. x × 120/100 = 240. x = 240×100/120 = 200.