A factory has 4 planning departments (1,2,3,4). Product A is manufactured according to the sequence 1-2-3-4 and product 2 according to the sequence 3-4-2-1-2. The daily production volumes of products A and B are 10 and 20 parts, respectively. (a) Construct the from-to-chart indicating the number of trips from one department to another. (b) Develop a relationship chart following these rules: “A” for any two departments with a total number of trips (including both directions) equal to 40 or more, “E” for 30 or more but less than 40; “I” for 20 or more but less than 30; “O” for 10 or more but less than 20; “U” for less than 10. Show all your calculations.