Arun sold an article at a profit of 10%. If he had purchased it at 10% less and sold it for Rs. 28 more, he would have gained 30%. Find the cost price of the article.

Let the cost price of article is  = Rs. 100Profit % = 10 %Profit = 10/100 x 100 = Rs. 10Selling price = Cost Price + Profit                       = 100 + 10                         = Rs. 110If he had  purchased it at 10 %less 10% of Rs. 100 10/100 x 100 =Rs. 10 then cost Price will be = 100 - 10 = Rs. 90 He sold it at 30% Profit Profit=30% of Rs. 90              = 30/100 x 90                = Rs. 27 Selling Price = Cost Price + Profit

                             = 90 + 27

                                = Rs. 117 Difference in selling Price =  117 - 110 = Rs. 7

If difference in Selling Price is Rs 7 then Cost Price is =Rs. 100If difference in Selling Price is Rs.1then Cost Price is 100/7If difference in Selling Price is Rs.28 then Cost Price =                                                                                =  100/7 x 28                                                                                  = 400      so Cost Price of article is Rs. 400