A person loses 20% when he sells an article for ₹230. What percentage will he gain, if he sells it for ₹339.25?

Let's assume the cost price of the article is ₹100y.

A person loses 20% when he sells an article for ₹230.

100y of (100-20)% = 230

100y of 80% = 230

80y = 230

$$y=\frac{23}{8}$$

the cost price of the article = ₹100y

= $$100\times\frac{23}{8}$$

= $$\frac{2300}{8}$$

= 287.5

Profit percentage = $$\frac{(selling\ price-\cos t\ price)}{\cos t\ price}\times100$$

= $$\frac{(339.25-287.5)}{287.5}\times100$$

= $$\frac{51.75}{287.5}\times100$$

= 18%