OCR Further Discrete 2018 September — Question 1

Exam BoardOCR
ModuleFurther Discrete (Further Discrete)
Year2018
SessionSeptember
TopicRoute Inspection

1 The design for the lines on a playing area for a game is shown below. The letters are not part of the design.
\includegraphics[max width=\textwidth, alt={}, center]{22571082-016b-409b-bfeb-e7ebf48ccac7-2_350_855_388_605} Priya paints the lines by pushing a machine. When she is pushing the machine she is about a metre behind the point being painted. She must not duplicate any line by painting it twice.
  • To relocate the machine, it must be stopped and then started again to continue painting the lines.
  • When the machine is being relocated it must still be pushed along the lines of the design, and not 'cut across' on a diagonal for example.
  • The machine can be turned through \(90 ^ { \circ }\) without having to be stopped.
    1. What is the minimum number of times that the machine will need to be started to paint the design?
The design is horizontally and vertically symmetric. $$\mathrm { AB } = 6 \text { metres, } \mathrm { AE } = 26 \text { metres, } \mathrm { AF } = 1.5 \text { metres and } \mathrm { AS } = 9 \text { metres. }$$
  • (a) Find the minimum distance that Priya needs to walk to paint the design. You should show enough working to make your reasoning clear but you do not need to use an algorithmic method.
    (b) Why, in practice, will the distance be greater than this?
    (c) What additional information would you need to calculate a more accurate shortest distance?