A shopkeeper gives two successive discounts on an article marked Rs. 450. The first discount given is 10 percent. If the customer pays Rs. 344.25 for the article, the second discount gives is = ?

$$\eqalign{ & {\text{Marked price of an article}} \cr & = {\text{Rs}}{\text{. 450}} \cr & {\text{After 1st discount}} \cr & = {\text{450}} \times \frac{{90}}{{100}} \cr & = {\text{Rs}}{\text{. 405}} \cr & {\text{Cost price of an article}} \cr & = {\text{Rs}}{\text{. 344}}{\text{.25}} \cr & {\text{Difference}} \cr & = {\text{Rs}}{\text{. 405}} - 344.25\, \cr & = {\text{Rs}}{\text{. 60}}{\text{.75}} \cr & {\text{2nd discount}} \cr & = \frac{{60.75}}{{405}} \times 100 \cr & = 15\% \cr} $$