North West Corner Rule:
Step1: The first assignment is made in the cell occupying the upper left hand ( north west ) corner of the transportation table. The maximum possible amount is allocated there. That is X11 min ( aa1 , b1) this value of X11 is then entered in the cell ( 1, 1) of the transportation table.
Step 2 :
a. If b1> a1 move vertically downwards to the second row and make the second allocation of amount X21 = min ( a1 b1- X11) in the cell ( 2,1,).
b. If b1 < a1 move horizontally right side to the second column and make the second allocation of amount X12 min ( a1- X11 , b2 ) in the cell (1,2).
c. If b1 = a1 there is a tie for the second allocation . one can make the second allocation of magnitude X12 = min ( a1- a1, b2 ) = 0 in the cell ( 1,2) or X21 = min ( a2 b1- b1) = o in the cell ( 2,1)
Step 3: Start from the new north west corner of the transportation table and repeat steps 1 an d2 until all the requirements are satisfied.