Profit = Selling Price - Cost Price Profit percent (\%) is the amount of the profit expressed in terms of percentage. The profit is based on the cost price, hence the formula to profit \% is (Profit/Cost Price) ×100 But profit = Selling Price - Cost Price Hence profit \% = ([Selling Price-Cost Price]/Cost Price) ×100 From the question, cost price (bought) =1500 Profit \% = 20\% Selling price = ? Let the selling price be x Get rid of the denominator by multiplying both sides of the equation by the L.C.M Every number is divisible by 1 , hence 20=20∕1 The L.C.M of 1500 and 1 is 1500 , hence multiply both sides by 1500 and cancel out 100×(x−1500)=20×1500 100×x−100×1500=30000 100x−150000=30000 100x=30000+150000 100x=180000 Divide both sides by 100 x=1800