a factory has 15 machines of equal efficiency in its factory . the annual manufacturing costs are rs . 42000 & establishment charges are rs . 12000 . the annual output of the company is rs . 70000 . the annual output and manufacturing costs are directly proportional to the number of machines . the shareholders get 12 . 512.5 profit , which is directly proportional to the annual output of the company . if 7 . 147.14 machines remain closed throughout the year , then the % decrease in the amountof profit of the shareholders would be ?