A shopkeeper buys 12 notebooks for ₹240 and sells each notebook for ₹25. Find his profit percentage.

**Profit** = SP − CP, when SP > CP. **Loss** = CP − SP, when CP > SP. Always positive — never write a negative profit; just call it a loss.

**Profit % $=\frac{\text{Profit}}{\text{CP}}\times 100$.** **Loss % $=\frac{\text{Loss}}{\text{CP}}\times 100$.** Both are calculated **on the cost price**, not the selling price.

Example: bought a pen for ₹40, sold for ₹50. Profit = ₹10. Profit % = $\frac{10}{40}\times 100=25\%$.