how it solve it by maximal spanning tree

Q11-31 South Side Oil and Gas, a new venture in Texas, has developed an oil pipeline network to transport oil from exploration fields to the refinery and other locations. There are 10 pipelines (branches) in the network. The oil flow in hundreds of gallons and the network of pipelines is given in the following table. (a) What is the maximum that can flow through the network? START END REVERSE BRANCH NODE NODE CAPACITY CAPACITY FLOW Branch 1 1 2 10 4 10 Branch 2 1 3 8 2 5 Branch 3 2 4 12 1 10 Branch 4 2 5 6 6 0 Branch 5 3 5 8 Branch 6 4 6 10 Branch 7 5 6 10 Branch 8 5 7 5 Branch 9 6 8 10 Branch 10 7 8 10 12051- 5 10 0 5 10 5