A shopkeeper sold two articles, one at a gain of 20% and the other at a loss of 20%. If the selling price of both were the same, how much percent did he gain or loss on the whole? एक दुकानदार दो वस्तुओं, एक को 20 प्रतिशत लाभ पर तथा दूसरी को 20 प्रतिशत हानि पर बेचता हैं। यदि दोनों का विक्रय मूल्य समान हो, तो सम्पूर्ण पर उसे कितना लाभ या हानि प्राप्त हुई?

When selling two items at the same SP with one at 20% gain and another at 20% loss, the net outcome is always a loss. The loss amount (based on higher CP) is always greater than the profit amount (based on lower CP). For equal SPs, the net loss percentage is (20/2)² = 4%. Here: if SP = 120, CP1 = 100; if SP = 80, CP2 = 100. Total CP = 200, total SP = 200, which initially seems balanced, but the actual calculation shows 4% overall loss.