Ratio and proportion

  • Circuit training
    problem

    Circuit Training

    Age
    14 to 16
    Challenge level
    Mike and Monisha meet at the race track, which is 400m round. Just to make a point, Mike runs anticlockwise whilst Monisha runs clockwise. Where will they meet on their way around and will they ever meet at the start again? If so, after how many circuits?
  • Tuning and Ratio
    problem

    Tuning and Ratio

    Age
    16 to 18
    Challenge level
    Why is the modern piano tuned using an equal tempered scale and what has this got to do with logarithms?
  • Eudiometry
    problem

    Eudiometry

    Age
    16 to 18
    Challenge level
    When a mixture of gases burn, will the volume change?
  • Diamonds aren't forever
    problem

    Diamonds Aren't Forever

    Age
    16 to 18
    Challenge level
    Ever wondered what it would be like to vaporise a diamond? Find out inside...
  • How big?
    problem

    How Big?

    Age
    11 to 14
    Challenge level
    If the sides of the triangle in the diagram are 3, 4 and 5, what is the area of the shaded square?
  • Slippage
    problem

    Slippage

    Age
    14 to 16
    Challenge level
    A ladder 3m long rests against a wall with one end a short distance from its base. Between the wall and the base of a ladder is a garden storage box 1m tall and 1m high. What is the maximum distance up the wall which the ladder can reach?
  • Reductant ratios
    problem

    Reductant Ratios

    Age
    16 to 18
    Challenge level
    What does the empirical formula of this mixture of iron oxides tell you about its consituents?
  • Gassy information
    problem

    Gassy Information

    Age
    16 to 18
    Challenge level
    Do each of these scenarios allow you fully to deduce the required facts about the reactants?
  • At a glance
    problem

    At a Glance

    Age
    14 to 16
    Challenge level
    The area of a regular pentagon looks about twice as a big as the pentangle star drawn within it. Is it?
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