D1 January 2012 Q4
4.

Figure 5 models a network of roads. The number on each edge gives the time, in minutes, taken to travel along that road. Olivia wishes to travel from A to J as quickly as possible.
On a particular day Olivia must include G in her route.
| Scheme | Marks |
|---|---|
![]() | M1 A1(BCH) A1ft(DE) A1ft(FG) A1(IJ) |
| ACHFIJ | B1 |
| 114 minutes | B1ft |
| (7) |
Notes
In (a) Accept any rising sequence for order of labelling. Order of working values is crucial.
a1M1: Big replaced by small in working values at least once at D or F or I or J.
a1A1: A, B, C, H boxes all correct, condone lack of 0 in A’s working value
a2A1ft: E and D ft, based on their order of labelling. Penalise order of labelling only once.
a3A1ft: G and F ft, based on their order of labelling. Penalise order of labelling only once.
a4A1: I and J CAO. Penalise order of labelling only once.
a1B1: Route CAO
a2B1ft: 114, or their final value ft.
| Scheme | Marks |
|---|---|
| Route: ABEGIJ length 115 (minutes) | B1, B1 |
| (2) | |
| (9 marks) |
Notes
b1B1: route CAO.
b2B1: length CAO.
