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)

21

MP : SP = 5 : 4 

Let the MP be 500, then SP = 400

Loss% = \(\frac{10}{3}\) % = \(\frac{1}{30}\)

CP = 30 units

SP = 30 - 1 = 29 units (given as 400)

29 units = 400

30 units = (\(\frac{400}{29}\)) × 30 = Rs. 413

If the article sold at MP

MP = New SP = 500

Profit = 500 - 413 = 87

∴ Required Profit% = (\(\frac{87}{413}\) )×100 = 21%