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Question 1 of 8

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Consider this plan of walking tracks between park locations. The graph is connected and can be drawn in planar form. Each edge label gives the walking distance in kilometres

Weighted investigation network. Vertices in listed order: [Gate | Shelter | Lake | Picnic Area | Wetland | Ranger Station]. Full edge list: Picnic Area–Lake (21 km); Ranger Station–Lake (25 km); Ranger Station–Shelter (7 km); Gate–Ranger Station (23 km); Lake–Shelter (31 km); Wetland–Lake (5 km); Wetland–Ranger Station (9 km).21 km25 km7 km23 km31 km5 km9 kmGateShelterLakePicnic AreaWetlandRanger Station
(a)3 marks

Count the vertices and edges, then use Euler's formula to find the number of faces

(b)1 mark

How many vertices have odd degree?

(c)1 mark

Can every connection be traversed exactly once while returning to the starting vertex? Select the correct verdict and reason

(d)1 mark

Find the shortest total walking distance from Shelter to Lake

(e)1 mark

Find the minimum total walking distance for a set of walking-track sections that reaches every vertex