. Currently 1% of the populations in a certain city are smokers. Based on a survey conducted each year 2 out of 100 non-smokers become smokers; and 1 out of 10 smokers become non- smokers. How many percent of the population will become smokers after two years? A manufacturer of refrigerator must ship at least 100 refrigerators to its two warehouses. Each warehouse holds a maximum of 100 refrigerators. Warehouse A holds 25 already, while warehouse B has 20 on hand. It costs Birr 100 to ship a refrigerator to warehouse A and birr 150 to warehouse B. How many refrigerators must be shipped to the two warehoused to minimize total cost? What is the minimum total cost