An article is sold at a certain price. If it is sold at 70% of this price, then there is a loss of 10%. What is the percentage profit, when it is sold at the original selling price?

$\frac{200}{7}$%

Let the article be originally sold for Rs. 90.

If it is sold at 70% of this price, the selling price would be

⇒ 90 × 70% = Rs. 63

So, the cost price of the article = 63 ÷ 0.9 = Rs. 70

Now, the profit% when it's sold at the original selling price = \(\frac{(90 - 70) × 100}{70}\) = $\frac{200}{7}$%