What percentage of profit would the shopkeeper have made if she had sold the dress at the original selling pri?

Tillo L: What percentage of profit would the shopkeeper have made if she had sold the dress at the original selling pri?
During a sale, a shopkeeper reduced the advertised selling price of a dress by 20%, resulting in a profit of 4% over her cost of the dress. What percentage of profit would the shopkeeper have made if she had sold the dress at the original selling price?

Answers and Views:

Answer by michiko_chand
Let the original advertised selling price of the dress be x.

He reduced the price by 20% which is (20/100)x

So he sold the dress at x-(20/100)x=0.8x

Now he made a profit of 4%.

Let the cost of the dress for the shopkeeper be y

Hence percentage profit= [(Selling Price – Cost price)/cost price]*100
or 4= [(0.8x-y)/y]*100
or 4 = (80x-100y)/y
or 4y=80x-100y
or 80x=104y
or 10x=13y
or y = 10x/13

Now if he had sold it at original price x, his profit would have been

[(x-y)/y]* 100

we know y = 10x/13

Hence profit = (x-10x/13)/ (10x/13) * 100
= (3/10)*100
=30%