Solution (By Examveda Team)
$$\eqalign{
& {\text{CP}} = 500 \cr
& {\text{SP}} = 576 \cr
& {\text{MP}} = 900\left[ {80\% \,{\text{above}}\,{\text{the}}\,{\text{CP}}} \right] \cr
& {\text{Now}}, \cr
& {\text{SP}} = {\text{MP}} \times {\left[ {1 - {\frac{R}{{100}}} } \right]^2} \cr
& \left[ {{\text{R = Rate}}\,{\text{of}}\,{\text{Discount}}} \right] \cr
& 576 = 900 \times {\left[ {1 - {\frac{R}{{100}}} } \right]^2} \cr
& R = 20\% \cr
& \cr
& {\text{Again}}, \cr
& {\text{SP}} = {\text{MP}} \times {\left[ {1 + {\frac{R}{{100}}} } \right]^2} \cr
& {\text{SP}} = 900 \times {\left[ {1 + {\frac{{20}}{{100}}} } \right]^2} \cr
& {\text{SP}} = 1296 \cr
& {\text{New}}\,{\text{Profit}}\,{\text{Percentage}}, \cr
& = {\frac{{ {SP - CP} }}{{CP}}} \times 100 \cr
& = {\frac{{ {1296 - 500} }}{{500}}} \times 100 \cr
& = 159.2\% \cr} $$
why we take in sp formula first tym - and second tym +