Production Planning and Control The company is a manufacturer of washing machines and dryers. In production, it is defined as an aggregate unit. The demand for products in 4 months is 500,600,700,600, respectively. One employee can produce 20 products per month in normal working hours. There are currently 25 employees and no overtime work. The factory can hire more workers but the cost per person is 4500$ and the cost of layoffs is 15000$ per person and the cost of working during normal hours is 550$ per unit per employee. The cost of keeping goods is 55$ per unit per month and the cost of late delivery is 120$ per unit per month. There is currently no inventory. Write a mathematical model. by setting goals that want to reduce all costs under specified conditions