A trader marked the price of a product in such a way that it is 20% more than the cost price. If he allows 10% discount on the marked price to the customer then his gain is -

Answer: Option A

Let Cost price= Rs. 100
Then,
Marked price = Rs. 120
Selling price = 90% of Rs. 120
$$\begin{array}{rl}& =\text{Rs}\text{.}\left(\frac{90}{100}\times 120\right)\\ & =\text{Rs}\text{.108}\end{array}$$
∴ Profit % = (108 - 100) % = 8%