Edexcel D1 2013 January — Question 6 13 marks

Exam BoardEdexcel
ModuleD1 (Decision Mathematics 1)
Year2013
SessionJanuary
Marks13
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicLinear Programming
TypeGraphical feasible region identification
DifficultyEasy -1.2 This is a standard D1 linear programming question requiring routine skills: reading constraints from a graph, formulating inequalities from word problems, shading feasible regions, and using point testing for optimization. All techniques are textbook exercises with no novel problem-solving required, making it easier than average A-level questions.
Spec7.06a LP formulation: variables, constraints, objective function7.06b Slack variables: converting inequalities to equations7.06d Graphical solution: feasible region, two variables7.06e Sensitivity analysis: effect of changing coefficients

6. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{bd6edbd4-1ec0-4c7e-bd39-b88f96bf52fb-6_1630_1461_219_301} \captionsetup{labelformat=empty} \caption{Figure 6}
\end{figure} Lethna is producing floral arrangements for an awards ceremony.
She will produce two types of arrangement, Celebration and Party.
Let \(x\) be the number of Celebration arrangements made.
Let \(y\) be the number of Party arrangements made.
Figure 6 shows three constraints, other than \(x , y \geqslant 0\) The rejected region has been shaded.
Given that two of the three constraints are \(y \leqslant 30\) and \(x \leqslant 60\),
  1. write down, as an inequality, the third constraint shown in Figure 6. Each Celebration arrangement includes 2 white roses and 4 red roses.
    Each Party arrangement includes 1 white rose and 5 red roses.
    Lethna wishes to use at least 70 white roses and at least 200 red roses.
  2. Write down two further inequalities to represent this information.
    (3)
  3. Add two lines and shading to Diagram 1 in the answer book to represent these two inequalities.
  4. Hence determine the feasible region and label it R . The times taken to produce each Celebration arrangement and each Party arrangement are 10 minutes and 4 minutes respectively. Lethna wishes to minimise the total time taken to produce the arrangements.
  5. Write down the objective function, T , in terms of \(x\) and \(y\).
  6. Use point testing to find the optimal number of each type of arrangement Lethna should produce, and find the total time she will take.

6.

\begin{figure}[h]
\begin{center}
  \includegraphics[alt={},max width=\textwidth]{bd6edbd4-1ec0-4c7e-bd39-b88f96bf52fb-6_1630_1461_219_301}
\captionsetup{labelformat=empty}
\caption{Figure 6}
\end{center}
\end{figure}

Lethna is producing floral arrangements for an awards ceremony.\\
She will produce two types of arrangement, Celebration and Party.\\
Let $x$ be the number of Celebration arrangements made.\\
Let $y$ be the number of Party arrangements made.\\
Figure 6 shows three constraints, other than $x , y \geqslant 0$\\
The rejected region has been shaded.\\
Given that two of the three constraints are $y \leqslant 30$ and $x \leqslant 60$,
\begin{enumerate}[label=(\alph*)]
\item write down, as an inequality, the third constraint shown in Figure 6.

Each Celebration arrangement includes 2 white roses and 4 red roses.\\
Each Party arrangement includes 1 white rose and 5 red roses.\\
Lethna wishes to use at least 70 white roses and at least 200 red roses.
\item Write down two further inequalities to represent this information.\\
(3)
\item Add two lines and shading to Diagram 1 in the answer book to represent these two inequalities.
\item Hence determine the feasible region and label it R .

The times taken to produce each Celebration arrangement and each Party arrangement are 10 minutes and 4 minutes respectively. Lethna wishes to minimise the total time taken to produce the arrangements.
\item Write down the objective function, T , in terms of $x$ and $y$.
\item Use point testing to find the optimal number of each type of arrangement Lethna should produce, and find the total time she will take.
\end{enumerate}

\hfill \mbox{\textit{Edexcel D1 2013 Q6 [13]}}