Edexcel D1 — Question 6

Exam BoardEdexcel
ModuleD1 (Decision Mathematics 1)
TopicNetwork Flows

6. The table below shows the maximum flows possible within a system.
To From\(S\)\(A\)\(B\)\(C\)D\(T\)
S-353055--
A-----50
B-12-8-20
C----1530
D-----14
T------
For example, the maximum flow from \(B\) to \(A\) is 12 units.
  1. Draw a digraph to represent this information.
  2. Give the capacity of the cut \(\{ S , A , B , C \} \mid \{ D , T \}\).
  3. Find the minimum cut, stating its capacity, and expressing it in the form \(\{ \quad \} \mid \{ \quad \}\).
  4. Use the labelling procedure to find the maximum flow from \(S\) to \(T\). You should list each flow-augmenting route you find together with its flow.
  5. Explain how you know that you have found the maximum possible flow.
  6. Give an example of a practical situation that could be modelled by the original table.