OCR Further Discrete 2018 December — Question 1 7 marks

Exam BoardOCR
ModuleFurther Discrete (Further Discrete)
Year2018
SessionDecember
Marks7
TopicDynamic Programming
TypeZero-sum game stable solution
DifficultyStandard +0.8 This is a Further Maths game theory question requiring systematic calculation of 16 outcomes, understanding of zero-sum games, and construction of a 4×4 pay-off matrix. While the concepts are standard for Further Discrete, the computational burden and need to carefully evaluate powers (e.g., 2^5 vs 5^2) across all cases makes it moderately challenging but still within typical Further Maths scope.
Spec7.08a Pay-off matrix: zero-sum games7.08b Dominance: reduce pay-off matrix

1 Arif and Bindiya play a game as follows.
  • They each secretly choose a positive integer from \(\{ 2,3,4,5 \}\).
  • They then reveal their choices. Let Arif's choice be \(A\) and Bindiya's choice be \(B\).
  • If \(A ^ { B } \geqslant B ^ { A }\), Arif wins \(B\) points and Bindiya wins \(- 4 - B\) points.
  • If \(A ^ { B } < B ^ { A }\), Arif wins \(- 4 - A\) points and Bindiya wins \(A\) points.

Question 1:
AnswerMarks Guidance
10 0
72
74
28
7
Question 1:
1 | 0 | 0 | 0 | 0 | 0 | 3
7 | 2
7 | 4
28
7
1 Arif and Bindiya play a game as follows.

\begin{itemize}
  \item They each secretly choose a positive integer from $\{ 2,3,4,5 \}$.
  \item They then reveal their choices. Let Arif's choice be $A$ and Bindiya's choice be $B$.
  \item If $A ^ { B } \geqslant B ^ { A }$, Arif wins $B$ points and Bindiya wins $- 4 - B$ points.
  \item If $A ^ { B } < B ^ { A }$, Arif wins $- 4 - A$ points and Bindiya wins $A$ points.
\begin{enumerate}[label=(\alph*)]
\item Assuming that each of the 16 possible outcomes is equally likely to be chosen, show that the average amount won by Arif is 0 .
\item \begin{enumerate}[label=(\roman*)]
\item Describe how to convert this game to a zero-sum game.
\item Construct the pay-off matrix for this zero-sum game, with Arif on rows.
\end{itemize}
\end{enumerate}\end{enumerate}

\hfill \mbox{\textit{OCR Further Discrete 2018 Q1 [7]}}