A shop keeper sold an article at four-fifth of the marked price and suffered a loss of $$3 \frac{1}{3}\%$$. Find the profit percent, if he sold the article at the marked price. (correct to nearest integer)

Let the cost price of the article = 100C

Loss = $$3 \frac{1}{3}\%$$ = $$\frac{10}{3}\%$$

Selling price of the article = 100C - $$\frac{\frac{10}{3}}{100}\times$$100C

= $$\frac{290}{3}$$C

Shop keeper sold the article at four-fifth of the marked price.

$$\frac{290}{3}$$C = $$\frac{4}{5}\times$$Marked price of the article

Marked price of the article = $$\frac{725}{6}$$C

Profit percentage when article is sold at marked price = $$\frac{\frac{725}{6}C-100C}{100C}\times100$$

= $$\frac{125C}{6\times100C}\times100$$

= 20.833%

= 21% (approximately)

Hence, the correct answer is Option C