15% of the marked price of an item is equal to 25% of its cost price. If a discount of 25% is given on the sale of the item, then what will be the profit percentage?

15% of the marked price of an item is equal to 25% of its cost price.

15% of the marked price = 25% of cost price

$$\frac{marked\ price}{cost\ price} = \frac{25\%}{15\%}$$

$$\frac{marked\ price}{cost\ price} = \frac{5}{3}$$

So let's assume the marked price and cost price is '5y' and '3y' respectively.

If a discount of 25% is given on the sale of the item.

Selling price = 5y of (100-25)%

= 5y of 75%

= $$5y\times\frac{75}{100}$$

= $$5y\times\frac{3}{4}$$

= $$\frac{15y}{4}$$

= 3.75y

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

= $$\frac{(3.75y-3y)}{3y}\times100$$

= $$\frac{(0.75y)}{3y}\times100$$

= $$\frac{75y}{3y}$$

= 25%