A shopkeeper sells 25 articles at Rs. 45 per article after giving 10% discount and earns 50% profit. If the discount is not given, the profit gained is = ?

Answer: Option D

Selling price of 1 article = Rs. 45
Let marked price of each article be Rs. x
Then,
$$\begin{array}{rl}& \frac{90}{100}x=45\\ & x=\text{Rs}\text{.}\left(\frac{45\times 100}{90}\right)\\ & =\text{Rs}\text{. 50}\\ & \text{CP}=\text{Rs}\text{.}\left(\frac{100}{150}\times 45\right)\\ & =\text{Rs}\text{. 30}\end{array}$$
When no discount is given,
Cost price = Rs. 30,
Selling price = Rs. 50
∴ Required profit %
$$\begin{array}{rl}& =\left(\frac{20}{30}\times 100\right)\%\\ & =66\frac{2}{3}\%\end{array}$$