Fill in the blanks.
1. In a transportation problem, we must make the number of ________ and _______ equal.
2. ______ or ______ are used to balance an assignment problem.
3. The method of finding an initial solution based on opportunity costs is called _______
4. ________ occurs when the number of occupied squares is less than the number of rows plus the number of columns minus one.
5. Both transportation and assignment problems are members of a category of LP problems called ________
6. In the case of an unbalanced problem, shipping cost coefficients of ______ are assigned to each dummy factory or warehouse.