Profit And Loss

A sells an umbrella to B at a loss of 20%, B sells it to C at a loss of 10% and finally C sells it to D at a loss of 5%. If D bought that umbrella at 342, at what cost had A bought it?

A person bought mangoes at the rate of 45 for 10 mangoes. Then he sold them at the rate of ₹ 60 for a dozen mangoes. What will be his profit or loss percentage ?