A shopkeeper buys an item for ₹1230. He marks it 30% above cost price and gives a discount of 15%. What is the profit or loss percentage?

After comparing cost and selling values, the result is 10.49%. First apply discount to marked price to obtain selling price; then compare selling price with cost price. The question-specific working supplied in the record is: MP = CP × (100 + markup%) /100 = 1230×130/100 = 1599. SP = MP × (100 − discount%)/100 = 1359. Profit% = (129/1230)×100 = 10.49%. Profit and loss questions become unreliable when a percentage is applied to the wrong base. Profit or loss percent uses cost price, while discount percent uses marked price. If several changes occur, convert each change into a multiplier and apply them in order. The distractors 15.49%, 5.49%, 20.49% can result from interchanging cost price and selling price, treating discount as loss, adding successive rates, ignoring quantity, or rounding before the final step. A dependable check is to assume cost price 100 whenever only percentages are involved, reconstruct the selling value, and compare the resulting ratio with the selected option. Also verify direction: profit requires selling price above cost price, whereas loss requires it below cost price. This method preserves the numerical relationships in the stem and develops formula selection, percentage-base recognition and option elimination for SSC, Railway, Banking and other competitive aptitude examinations.