A trader sells two pen sets for equal selling prices. On one he makes 18% profit and on the other 18% loss. What is the net loss percentage?

Correct percentage analysis gives 3.24% Loss, corresponding to option B. Apply the profit or loss multiplier to cost price: SP = CP(1 ± rate/100). The question-specific working supplied in the record is: This Profit and Loss solved example uses the equal selling price shortcut trick: when one item gains 18% and the other loses 18%, the combined result is always a loss. The step-by-step formula is net loss percentage = (18/10)² = 3.24%. Equal gain and loss percentages do not cancel because the two cost prices are different even though the selling prices are equal. Taking the same selling price for both items and comparing their cost prices confirms the 3.24% loss. Therefore, the net result is 3.24% loss, matching option C.. 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 5.24% Loss, 4.24% Loss, 2.24% Loss 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.