A carpenter's cost of making a stool is ₹640 and he wants a profit of 35% on his cost. At what price should he sell it?

**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 % = $\frac{10}{40}\times 100=25\%$.