Please help I can't figure this out using excel

The Shamrock Transportation Company has four terminals: A, B, C, and D. At the start of a particular day, there are 8, 8, 6 , and 3 tractors available at those terminals, respectively. During the previous night, trailers were loaded at plants R, S, T, and U. The number of trailers at each plant is 2,12,5, and 6 , respectively. The company dispatcher has determined the distances between each terminal and each plant, as follows. Please: 1.) Use Greedy method to help the company figure out an acceptable solution. 2.) Assuming u=0, calculate Hi, and Yii (Please notice that you must set u=0, otherwise the answer will be considered wrong and receives 0 points). 3.) Based on ui and y, calculate sii for unused routes (squares). 4.) Based on yE, is the current solution (figured out by Greedy method) the optimal solution? Why? \begin{tabular}{|l|c|c|c|c|c|} \hline Travelling DistanceMatrix \\ \hline Shipments & Dest 1 & Dest 2 & Dest 3 & Dest 4 & Row Total \\ \hline Origin 1 & 21 & 44 & 25 & 40 & 8 \\ \hline Origin 2 & 42 & 24 & 45 & 22 & 8 \\ \hline Origin 3 & 78 & 32 & 42 & 55 & 6 \\ \hline Origin 4 & 44 & 42 & 32 & 30 & 3 \\ \hline Demand & 2 & 12 & 5 & 6 & \\ \hline \end{tabular} Question 4.)Based on wij, is the current solution (figured out by Greedy method) the optimal solution? Why? \begin{tabular}{|l|l|l|l|l|l|} \hline \multicolumn{7}{|c|}{ Calculate wi} \\ \hline wij & Dest 1 & Dest 2 & Dest 3 & Dest 4 & Ui \\ \hline Origin 1 & & & & & \\ \hline Origin 2 & & & & & \\ \hline Origin 3 & & & & & \\ \hline Origin 4 & & & & & \\ \hline Vj & & & & & \\ \hline \end{tabular}