Study Material — 16 PYQs (2020–2020) · Concept Notes · Shortcuts
SSC GD Constable Basic Profit & Loss is a frequently tested subtopic — 16 previous year questions from 2020–2020 papers are included below with concept notes, key rules and shortcut tricks.
A merchant buys notebooks at ₹8 each and sells them at ₹10 each. If he sells 200 notebooks, what is his profit percentage?
Exam Q 42020Previous Year Pattern
A trader buys 50 kg of rice at ₹40 per kg and sells it at ₹50 per kg. What is the total profit?
Exam Q 52020Previous Year Pattern
A vendor buys apples at ₹60 per dozen and sells them at ₹6 per apple. What is his profit percentage?
Exam Q 62020Previous Year Pattern
A shopkeeper marks an item at ₹500 and gives a discount of 10%. He still makes a profit of 25%. What is the Cost Price of the item?
Exam Q 72020Previous Year Pattern
A trader sells two items. On the first item, he makes a profit of 30%, and on the second item, he makes a loss of 20%. If the cost price of each item is ₹500, what is his overall profit or loss percentage?
Exam Q 82020Previous Year Pattern
A shopkeeper marks his goods 50% above the cost price. What discount percentage should he offer to make a profit of 20%?
Exam Q 92020Previous Year Pattern
A person buys a bicycle for ₹1200 and sells it at a loss of 15%. At what price did he sell the bicycle?
Exam Q 102020Previous Year Pattern
A retailer buys 100 items at ₹50 each. He sells 60 items at ₹75 each and the remaining items at ₹40 each. What is his overall profit or loss percentage?
Exam Q 112020Previous Year Pattern
A merchant buys goods for ₹2400. He wants to mark them such that after giving a 20% discount, he still makes a 25% profit. What should be the marked price?
Exam Q 122020Previous Year Pattern
A shopkeeper buys a watch for ₹800 and marks it at 60% above the cost price. If he offers a discount of 25% on the marked price, what is his profit percentage?
Exam Q 132020Previous Year Pattern
A retailer buys goods at ₹2400 per box. He marks them 50% above cost price and offers a discount of 25% on the marked price. Additionally, he gives a free item worth ₹100 with each box sold. What is his profit or loss percentage per box?
Exam Q 142020Previous Year Pattern
A shopkeeper buys 120 articles at ₹15 each. He sells 80% of them at ₹20 each and the remaining at ₹12 each. What is his overall profit percentage?
Exam Q 152020Previous Year Pattern
A merchant marks his goods 40% above cost price. He gives a discount of 20% on the marked price. If he earns a profit of ₹240, what is the cost price of the goods?
Exam Q 162020Previous Year Pattern
A trader bought two items for ₹3000 each. He sold the first item at a profit of 25% and the second at a loss of 20%. What is his overall profit or loss percentage?
Concept Notes
Basic Profit & Loss— Rules & Concept
💡
Core Concept
Read this first — the foundation of the topic
→Core Concept
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
💡Key Terms
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)
20% profit on one item, 20% loss on another = Overall loss of 4%
✏️Worked Example 1
1
Identify CP = Rs. 800, SP = Rs. 920
2
Calculate Profit = SP - CP = 920 - 800 = Rs. 120
3
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
1
SP = Rs. 1440, Loss% = 20%
2
Use shortcut CP = SP/(1 - Loss%/100) = SP/0.8
3
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.
Key Points to Remember
Profit occurs when Selling Price > Cost Price, Loss occurs when Cost Price > Selling Price
Profit% and Loss% are always calculated on Cost Price, never on Selling Price
Quick formula: SP = CP × (100 ± gain%)/100 where + for profit, - for loss
Shortcut: When profit% equals loss% in two transactions, overall result is always loss