Networks/graph theory

  • Limiting Probabilities
    problem
    Favourite

    Limiting Probabilities

    Age
    16 to 18
    Challenge level
    filled star filled star filled star
    Given probabilities of taking paths in a graph from each node, use matrix multiplication to find the probability of going from one vertex to another in 2 stages, or 3, or 4 or even 100.
  • Tourism
    problem
    Favourite

    Tourism

    Age
    11 to 16
    Challenge level
    filled star filled star empty star

    If you can copy a network without lifting your pen off the paper and without drawing any line twice, then it is traversable. Decide which of these diagrams are traversable.

  • Plum Tree
    problem

    Plum Tree

    Age
    14 to 18
    Challenge level
    filled star empty star empty star
    Label this plum tree graph to make it totally magic!
  • Knight Defeated
    problem

    Knight Defeated

    Age
    14 to 16
    Challenge level
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    The knight's move on a chess board is 2 steps in one direction and one step in the other direction. Prove that a knight cannot visit every square on the board once and only (a tour) on a 2 by n board for any value of n. How many ways can a knight do this on a 3 by 4 board?
  • W Mates
    problem

    W Mates

    Age
    16 to 18
    Challenge level
    filled star empty star empty star
    Show there are exactly 12 magic labellings of the Magic W using the numbers 1 to 9. Prove that for every labelling with a magic total T there is a corresponding labelling with a magic total 30-T.
  • Only connect
    problem

    Only Connect

    Age
    11 to 14
    Challenge level
    filled star empty star empty star
    The graph represents a salesman’s area of activity with the shops that the salesman must visit each day. What route around the shops has the minimum total distance?
  • Travelling Salesman
    problem

    Travelling Salesman

    Age
    11 to 14
    Challenge level
    filled star empty star empty star
    A Hamiltonian circuit is a continuous path in a graph that passes through each of the vertices exactly once and returns to the start. How many Hamiltonian circuits can you find in these graphs?
  • Maximum Flow
    problem

    Maximum Flow

    Age
    16 to 18
    Challenge level
    filled star empty star empty star
    Given the graph of a supply network and the maximum capacity for flow in each section find the maximum flow across the network.
  • Placeholder: several colourful numbers
    problem

    Round-Robin Scheduling

    Age
    7 to 14
    Challenge level
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    Think about the mathematics of round robin scheduling.
  • Factors and multiples graphs
    problem

    Factors and Multiples Graphs

    Age
    16 to 18
    Challenge level
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    Explore creating 'factors and multiples' graphs such that no lines joining the numbers cross