a merchant marks his goods up by 30 % and then offers a discount of 10 % on the marked price . what % profit does the merchant make after the discount ?
"let the price be 100 . the price becomes 130 after a 30 % markup . now a discount of 10 % on 130 . profit = 117 - 100 17 % answer a"
subtract(subtract(add(30, const_100), divide(multiply(add(30, const_100), 10), const_100)), const_100)