A dishonest dealer sells the goods at 7% loss on cost price but uses 18% less weight. What is his percentage of profit? (Correct to 2 decimal places)

Answer: Option D

As, Loss (a) = 7% and Less weight (b) = 18%
Then,
$$\begin{array}{rl}& \frac{\text{Profit }\%}{\text{Loss }\%}=\frac{\text{b}\pm \text{a}}{100-\text{b}}\times 100\\ & \Rightarrow \frac{18-7}{100-18}\times 100\\ & \Rightarrow \frac{11}{82}\times 100\\ & \Rightarrow 13.4146\approx 13.41\%\end{array}$$
∴ The dealer's profit % is 13.41%.