Visualising and representing

  • All in the Mind
    problem

    All in the Mind

    Age
    11 to 14
    Challenge level
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    Imagine you are suspending a cube from one vertex and allowing it to hang freely. What shape does the surface of the water make around the cube?
  • Fermat's Poser
    problem

    Fermat's Poser

    Age
    14 to 16
    Challenge level
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    Find the point whose sum of distances from the vertices (corners) of a given triangle is a minimum.
  • Dissect
    problem

    Dissect

    Age
    11 to 14
    Challenge level
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    What is the minimum number of squares a 13 by 13 square can be dissected into?
  • Painting Cubes
    problem

    Painting Cubes

    Age
    11 to 14
    Challenge level
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    Imagine you have six different colours of paint. You paint a cube using a different colour for each of the six faces. How many different cubes can be painted using the same set of six colours?
  • Hypotenuse Lattice points
    problem

    Hypotenuse Lattice Points

    Age
    14 to 16
    Challenge level
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    The triangle OMN has vertices on the axes with whole number co-ordinates. How many points with whole number coordinates are there on the hypotenuse MN?
  • Hallway Borders
    problem

    Hallway Borders

    Age
    11 to 14
    Challenge level
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    What are the possible dimensions of a rectangular hallway if the number of tiles around the perimeter is exactly half the total number of tiles?
  • On Time
    problem

    On Time

    Age
    11 to 14
    Challenge level
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    On a clock the three hands - the second, minute and hour hands - are on the same axis. How often in a 24 hour day will the second hand be parallel to either of the two other hands?
  • Trice
    problem

    Trice

    Age
    11 to 14
    Challenge level
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    ABCDEFGH is a 3 by 3 by 3 cube. Point P is 1/3 along AB (that is AP : PB = 1 : 2), point Q is 1/3 along GH and point R is 1/3 along ED. What is the area of the triangle PQR?
  • Linkage
    problem

    Linkage

    Age
    11 to 14
    Challenge level
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    Four rods, two of length a and two of length b, are linked to form a kite. The linkage is moveable so that the angles change. What is the maximum area of the kite?
  • Around and Back
    problem

    Around and Back

    Age
    14 to 16
    Challenge level
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    A cyclist and a runner start off simultaneously around a race track each going at a constant speed. The cyclist goes all the way around and then catches up with the runner. He then instantly turns around and heads back to the starting point where he meets the runner who is just finishing his first circuit. Find the ratio of their speeds.