When a shirt is sold for ₦12,000 at a 20% loss, it means ₦12,000 is 80% of the cost price. Find the Cost Price (CP) CP = \(\frac{12,000}{80\%} = \frac{12,000}{0.8}\) = ₦15,000 Find the selling price for 20% gain To gain 20%, the new selling price should be 120% of the cost price. SP = 120\(\% \text{ of } ₦15,000 = 1.2 \times\) 15,000 = ₦18,000.