Gain Percentage on Remaining Goods

Total cost = Rs. 1000. Desired profit = $20\%$ of $1000 = \text{Rs. } 200$. Total target revenue = Rs. 1200. $\frac{1}{4}$ of goods cost Rs. 250, sold at $10\%$ loss $\Rightarrow$ revenue = $250 \times 0.9 = \text{Rs. } 225$. Remaining revenue needed = $1200 - 225 = \text{Rs. } 975$. Cost of remaining goods = Rs. 750. Gain required on remaining goods = $975 - 750 = \text{Rs. } 225$. Percentage gain = $\frac{225}{750} \times 100 = 30\%$.