To find the discount of an item you put the rate which is 25% over 100 and move the decimal point to the right this would leave you with 0.25.You then times $40 by 0.25 which leaves you with $10 so $10 is your discount.
To find the sales price of the dress you subtract the discounted price from the original price so it would be $40-$10 which is $30 so your sales price is $30.
