Union Express has 60 tons of cargo that need to be shipped from Boston to Dallas. The shipping capacity 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 tons

boston to pittsburgh          25 tons

boston to cincinnati           35 tons

baltimore to atlanta          10 tons

baltimore to cincinnati        5 tons

pittsburgh to atlanta         15 tons

pittsburgh to chicago        20 tons

cincinnati to chicago         15 tons

cincinnati to memphis        5 tons

atlanta to memphis          25 tons

atlanta to dallas               10 tons

chicago to memphis         20 tons

chicago to dallas              15 tons

memphis to dallas            30 tons

memphis to chicago         15 tons

Will Union Express be able to move all 60 tons from boston to dallas in one night?

a. Draw a network flow model for this problem.

b. Create a spreadsheet model for the problem and solve it.

c. what is the maximum flow for this network?