Union Express has 60 tons of cargo that need to be ship

Union Express has 60 tons of cargo that need to be shipped from Boston to Dallas.
The shipping capacities on each of the routes Union Express planes fly each night is shown in the following table:
Nightly Flight Segments Capacity (in tons)
Boston to Baltimore 30
Boston to Pittsburgh 25
Boston to Cincinnati 35
Baltimore to Atlanta 10
Baltimore to Cincinnati 5
Pittsburgh to Atlanta 15
Pittsburgh to Chicago 20
Cincinnati to Chicago 15
Cincinnati to Memphis 5
Atlanta to Memphis 25
Atlanta to Dallas 10
Chicago to Memphis 15
Chicago to Dallas 15
Memphis to Dallas 30
Memphis to Chicago 15
Will Union Express be able to move all 60 tons from Boston to Dallas in one night?
Draw a network flow model for this problem
Create a spreadsheet model for the problem and solve it.
What is the maximum flow for this network?
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