Edexcel FD2 AS (Further Decision 2 AS) Specimen

Question 1
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  1. Six workers, A, B, C, D, E and F, are to be assigned to five tasks, P, Q, R, S and T.
Each worker can be assigned to at most one task and each task must be done by just one worker. The time, in minutes, that each worker takes to complete each task is shown in the table below.
PQRST
A3232353433
B2835313740
C3529333635
D3630343335
E3031293736
F2928323134
Reducing rows first, use the Hungarian algorithm to obtain an allocation which minimises the total time. You must explain your method and show the table after each stage.
Question 2
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2. In two-dimensional space, lines divide a plane into a number of different regions. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{81510c1c-89ce-4fa8-aa1b-3c8b255804cc-3_421_328_306_278} \captionsetup{labelformat=empty} \caption{Figure 1}
\end{figure} \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{81510c1c-89ce-4fa8-aa1b-3c8b255804cc-3_423_330_306_671} \captionsetup{labelformat=empty} \caption{Figure 2}
\end{figure} \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{81510c1c-89ce-4fa8-aa1b-3c8b255804cc-3_426_330_303_1065} \captionsetup{labelformat=empty} \caption{Figure 3}
\end{figure} \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{81510c1c-89ce-4fa8-aa1b-3c8b255804cc-3_423_332_306_1457} \captionsetup{labelformat=empty} \caption{Figure 4}
\end{figure} It is known that:
  • One line divides a plane into 2 regions, as shown in Figure 1
  • Two lines divide a plane into a maximum of 4 regions, as shown in Figure 2
  • Three lines divide a plane into a maximum of 7 regions, as shown in Figure 3
  • Four lines divide a plane into a maximum of 11 regions, as shown in Figure 4
    1. Complete the table in the answer book to show the maximum number of regions when five, six and seven lines divide a plane.
    2. Find, in terms of \(\mathrm { u } _ { \mathrm { n } }\), the recurrence relation for \(\mathrm { u } _ { \mathrm { n } + 1 }\), the maximum number of regions when a plane is divided by ( \(n + 1\) ) lines where \(n \geqslant 1\)
      1. Solve the recurrence relation for \(u _ { n }\)
      2. Hence determine the maximum number of regions created when 200 lines divide a plane.
Question 3
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3.
\includegraphics[max width=\textwidth, alt={}]{81510c1c-89ce-4fa8-aa1b-3c8b255804cc-4_2255_54_315_34}
\begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{81510c1c-89ce-4fa8-aa1b-3c8b255804cc-4_913_1783_287_139} \captionsetup{labelformat=empty} \caption{Figure 5}
\end{figure} Figure 5 represents a network of corridors in a school. The number on each arc represents the maximum number of students, per minute, that may pass along each corridor at any one time. At 11 am on Friday morning, all students leave the hall (S) after assembly and travel to the cybercafé ( T ). The numbers in circles represent the initial flow of students recorded at 11 am one Friday.
  1. State an assumption that has been made about the corridors in order for this situation to be modelled by a directed network.
  2. Find the value of x and the value of y , explaining your reasoning. Five new students also attend the assembly in the hall the following Friday. They too need to travel to the cybercafé at 11 am . They wish to travel together so that they do not get lost. You may assume that the initial flow of students through the network is the same as that shown in Figure 5 above.
    1. List all the flow augmenting routes from S to T that increase the flow by at least 5
    2. State which route the new students should take, giving a reason for your answer.
  3. Use the answer to part (c) to find a maximum flow pattern for this network and draw it on Diagram 1 in the answer book.
  4. Prove that the answer to part (d) is optimal. The school is intending to increase the number of students it takes but has been informed it cannot do so until it improves the flow of students at peak times. The school can widen corridors to increase their capacity, but can only afford to widen one corridor in the coming term.
  5. State, explaining your reasoning,
    1. which corridor they should widen,
    2. the resulting increase of flow through the network.
Question 4
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4. A two person zero-sum game is represented by the following pay-off matrix for player A.
\cline { 2 - 4 } \multicolumn{1}{c|}{}B plays 1B plays 2B plays 3
A plays 1412
A plays 2243
  1. Verify that there is no stable solution.
    1. Find the best strategy for player A.
    2. Find the value of the game to her.