A dishonest dealer claims to sell his goods at cost price, but he uses a weight of lesser weight, then the gain% $$=\ \ \frac{\text{True Weight} - \text{False Weight}}{\text{False Weight}} \times 100\%$$
A dishonest dealer sells an item at a profit of x % and uses a weight that is y % less, then the gain% $$=\ \frac{\%\ \text{Profit} + \%\ \text{Less in Weight}}{100 - \%\ \text{Less in Weight}} \times 100\%$$
