If the selling price of an article is doubled, then its loss profit percent is converted into equal profit percent. The loss percent on the article is = ?

Let SP = Rs. x
According to question,
$$\eqalign{ & \left( {\frac{{CP - x}}{{CP}}} \right) \times 100 = \left( {\frac{{2x - CP}}{{CP}}} \right) \times 100 \cr & CP - x = 2x - CP \cr & 3x = 2CP \cr & x = \frac{2}{3}CP \cr & SP = \frac{2}{3}CP \cr & \frac{{SP}}{{CP}} = \frac{2}{3} > 1{\text{ unit loss}} \cr & {\text{Loss}}\% = \frac{1}{3} \times 100 = 33\frac{1}{3}\% \cr} $$