RRB Group D Basic Profit & Loss

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)

Profit% = (Profit/CP) × 100. Loss% = (Loss/CP) × 100. SP = CP + Profit = CP(100 + Profit%)/100. SP = CP - Loss = CP(100 - Loss%)/100.

CP = SP × 100/(100 + Profit%). CP = SP × 100/(100 - Loss%).

20% profit on one item, 20% loss on another = Overall loss of 4%

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

Students calculate percentage on Selling Price instead of Cost Price

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

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.