A dishonest dealer professes to sell his goods at the cost price but uses a false weight of 850 g. instead of 1 kg. his gain percent is = ?

Answer: Option B

According to the question,
Dishonest dealer sold at cost price uses a false weight of 850 gm. instead to 1 kg.
$$\begin{array}{rl}& \therefore \text{Profit }\%\\ & =\frac{150}{850}\times 100\\ & =17\frac{11}{17}\%\text{profit}\end{array}$$