Edexcel D1 2021 January — Question 7

Exam BoardEdexcel
ModuleD1 (Decision Mathematics 1)
Year2021
SessionJanuary
TopicLinear Programming

7. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{48e785c0-7de5-450f-862c-4dd4d169adf9-10_993_1268_221_402} \captionsetup{labelformat=empty} \caption{Figure 3}
\end{figure} Figure 3 shows the constraints of a linear programming problem in \(x\) and \(y\), where \(R\) is the feasible region. The equations of two of the lines have been shown in Figure 3. Given that \(k\) is a positive constant,
  1. determine, in terms of \(k\) where necessary, the inequalities that define \(R\). The objective is to maximise \(P = 5 x + k y\)
    Given that the value of \(P\) is 38 at the optimal vertex of \(R\),
  2. determine the possible value(s) of \(k\). You must show algebraic working and make your method clear.
    (Total 11 marks)