A person sold an article at a loss of 16%. Had he sold it for Rs. 660 more, he would have gained 8%. If the article is sold at Rs. 3,080, then how much profit percentage is gained?

$$\eqalign{ & 25x + \frac{{108}}{{100}} = 21x + 660 \cr & 6x = 660 \cr & x = 110 \cr & {\text{Cost price}} = 25 \times 11 = 2750 \cr & {\text{Selling price}} = 3080 \cr & {\text{Profit}} = 3080 - 2750 = 330 \cr & {\text{Profit }}\% = \frac{{330 \times 100}}{{2750}} = 12\% \cr} $$