By selling an article at $$\frac{2}{3}$$ of the marked price, there is a loss of 10% . The profit percent, when the article is sold at the marked price, is -

$$\eqalign{ & {\text{Let the M}}{\text{.P be Rs}}{\text{. }}x. \cr & {\text{Then,}} \cr & {\text{S}}{\text{.P}}{\text{.}} = {\text{Rs}}.\frac{2}{3}x,{\text{loss}} = 10\% \cr & {\text{C}}{\text{.P}}{\text{.}} = {\text{Rs}}.\left( {\frac{{100}}{{90}} \times \frac{2}{3}x} \right) \cr & \,\,\,\,\,\,\,\,\,\,\,\, = {\text{Rs}}.\frac{{20}}{{27}}x \cr & {\text{If an article is sold at M}}{\text{.P}}{\text{.}} \cr & {\text{Then,}} \cr & {\text{Profit}} = {\text{Rs}}.\left( {x - \frac{{20}}{{27}}x} \right) \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = {\text{Rs}}.\frac{{7x}}{{27}} \cr & \therefore {\text{Profit}}\% \cr & = \left( {\frac{{7x}}{{27}} \times \frac{{27}}{{20x}} \times 100} \right)\% \cr & = 35\% \cr} $$