16 questions from actual SSC GD Constable papers · all shown free · click option to reveal solution
When you buy something for Rs. 100 and sell it for Rs. 120, you make Rs. 20 profit. If you sell it for Rs. 80, you face Rs. 20 loss. This simple idea forms the basis of all profit-loss calculations
Cost Price (CP) = Price at which goods are purchased. Selling Price (SP) = Price at which goods are sold. Profit = SP - CP (when SP > CP). Loss = CP - SP (when CP > SP).
SSC CGL asks 2-3 direct profit-loss questions every year. Common question types include finding CP when SP and profit% are given, calculating overall profit/loss in multiple transactions, and finding marked price after discount. Powerful Shortcut #1: When profit% = loss%, overall result is always loss. Loss% = (Profit%)²/100. Example: 20% profit on one item, 20% loss on another = Overall loss of 4%.
Identify CP = Rs. 800, SP = Rs. 920
Calculate Profit = SP - CP = 920 - 800 = Rs. 120
Apply formula Profit% = (Profit/CP) × 100 = (120/800) × 100 = 15% Answer: 15% profit Shortcut #2: Quick CP calculation when SP and profit% known. Use: CP = SP/(1 + Profit%/100). For 25% profit, divide SP by 1.25. For 20% loss, divide SP by 0.8. Worked Example 2: An article is sold for Rs. 1440 at 20% loss. Find the cost price.
SP = Rs. 1440, Loss% = 20%
Use shortcut CP = SP/(1 - Loss%/100) = SP/0.8
CP = 1440/0.8 = Rs. 1800 Verification: 20% of 1800 = 360, so SP = 1800 - 360 = 1440 ✓ Answer: Rs. 1800 Shortcut #3: For successive transactions, multiply factors. 10% profit followed by 20% loss = 1.1 × 0.8 = 0.88, meaning 12% overall loss. Most Common Trap: Students calculate percentage on Selling Price instead of Cost Price. Remember: Profit% and Loss% are ALWAYS calculated on Cost Price, never on Selling Price. This mistake costs at least 1-2 marks in every exam. Another frequent error involves sign confusion. When CP > SP, it's a loss situation. When SP > CP, it's profit. Always check this relationship before applying formulas. Exam Strategy: Start with identifying what's given and what's asked. Write down CP, SP clearly. Apply the basic formula first, then use shortcuts for speed. Double-check by working backwards - if you found CP, calculate SP using the given profit% to verify your answer.