General Test — Percentages, profit and loss

Overview

Percentages appear across the General Test, from discounts to profit and interest. A few formulas cover most questions.

Key concepts

• x% of N = N × x ÷ 100.
• Percentage change = (change ÷ original) × 100.
• Profit% = (SP − CP) ÷ CP × 100. So SP = CP × (100 + profit%) ÷ 100.
• Simple interest = P × R × T ÷ 100.

Important points

• Profit and loss percentages are always calculated on the cost price.
• To convert km/h to m/s, multiply by 5/18.

Quick revision

Example: SP ₹540 at 20% profit → CP = 540 ÷ 1.2 = ₹450.