A trader purchased a gift box for Rs. 150. What should be the marked price on the gift box so that after allowing a discount of 10% , he makes a profit of 10% ?

$$\eqalign{ & {\text{Cost}}\,{\text{price}}\,{\text{of}}\,{\text{gift}}\, = {\text{Rs}}{\text{.}}\,150 \cr & {\text{Profit}}\% = 10\% \cr & {\text{SP}} = 150 + \left( {\frac{{10}}{{100}} + 150} \right) \cr & \,\,\,\,\,\,\,\,\,\, = 150 + 15 \cr & \,\,\,\,\,\,\,\,\,\, = {\text{Rs}}{\text{.}}\,165 \cr & {\text{Discount}}\% = 10\% \cr & {\text{MP}} = \frac{{165}}{{\left( {100 - 10} \right)}} \times 100 \cr & \,\,\,\,\,\,\,\,\,\,\,\, = \frac{{1650}}{9} \cr & \,\,\,\,\,\,\,\,\,\,\,\, \approx {\text{Rs}}{\text{.}}\,183.30 \cr} $$