AQA D1 2008 January — Question 8 8 marks

Exam BoardAQA
ModuleD1 (Decision Mathematics 1)
Year2008
SessionJanuary
Marks8
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicLinear Programming
TypeFormulation with percentage constraints
DifficultyStandard +0.3 This is a straightforward linear programming formulation question requiring students to translate word constraints into inequalities. While it involves five constraints including a percentage condition, the mathematical operations are routine: setting up resource constraints (≤ for availability) and minimum usage constraints (≥ for totals). The percentage constraint requires slightly more thought but is still mechanical. This is slightly easier than average as it's pure formulation with no optimization or graphical work required.
Spec7.06a LP formulation: variables, constraints, objective function7.06b Slack variables: converting inequalities to equations

8 Each day, a factory makes three types of hinge: basic, standard and luxury. The hinges produced need three different components: type \(A\), type \(B\) and type \(C\). Basic hinges need 2 components of type \(A , 3\) components of type \(B\) and 1 component of type \(C\). Standard hinges need 4 components of type \(A , 2\) components of type \(B\) and 3 components of type \(C\). Luxury hinges need 3 components of type \(A\), 4 components of type \(B\) and 5 components of type \(C\). Each day, there are 360 components of type \(A\) available, 270 of type \(B\) and 450 of type \(C\). Each day, the factory must use at least 720 components in total.
Each day, the factory must use at least \(40 \%\) of the total components as type \(A\).
Each day, the factory makes \(x\) basic hinges, \(y\) standard hinges and \(z\) luxury hinges.
In addition to \(x \geqslant 0 , y \geqslant 0 , z \geqslant 0\), find five inequalities, each involving \(x , y\) and \(z\), which must be satisfied. Simplify each inequality where possible.

Question 8:
AnswerMarks Guidance
Answer/WorkingMarks Guidance
\(2x+4y+3z \leq 360\)M1 Any correct LHS in inequality
\(3x+2y+4z \leq 270\) and \(x+3y+5z \leq 450\)A2,1,0 OE
\(6x+9y+12z \geq 720 \Rightarrow 2x+3y+4z \geq 240\)M1, A1 Allow further correct simplification
\(2x+4y+3z \geq \frac{2}{5}(6x+9y+12z)\)M1, A1 Must have 3 parts correct
\(2y \geq 2x+9z\) OEA1 Allow further correct simplification — 8 marks total
# Question 8:

| Answer/Working | Marks | Guidance |
|---|---|---|
| $2x+4y+3z \leq 360$ | M1 | Any correct LHS in inequality |
| $3x+2y+4z \leq 270$ and $x+3y+5z \leq 450$ | A2,1,0 | OE |
| $6x+9y+12z \geq 720 \Rightarrow 2x+3y+4z \geq 240$ | M1, A1 | Allow further correct simplification |
| $2x+4y+3z \geq \frac{2}{5}(6x+9y+12z)$ | M1, A1 | Must have 3 parts correct |
| $2y \geq 2x+9z$ OE | A1 | Allow further correct simplification — 8 marks total |
8 Each day, a factory makes three types of hinge: basic, standard and luxury. The hinges produced need three different components: type $A$, type $B$ and type $C$.

Basic hinges need 2 components of type $A , 3$ components of type $B$ and 1 component of type $C$.

Standard hinges need 4 components of type $A , 2$ components of type $B$ and 3 components of type $C$.

Luxury hinges need 3 components of type $A$, 4 components of type $B$ and 5 components of type $C$.

Each day, there are 360 components of type $A$ available, 270 of type $B$ and 450 of type $C$.

Each day, the factory must use at least 720 components in total.\\
Each day, the factory must use at least $40 \%$ of the total components as type $A$.\\
Each day, the factory makes $x$ basic hinges, $y$ standard hinges and $z$ luxury hinges.\\
In addition to $x \geqslant 0 , y \geqslant 0 , z \geqslant 0$, find five inequalities, each involving $x , y$ and $z$, which must be satisfied. Simplify each inequality where possible.

\hfill \mbox{\textit{AQA D1 2008 Q8 [8]}}