Inequalities

  • In Between
    problem

    In between

    Age
    16 to 18
    Challenge level
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    Can you find the solution to this algebraic inequality?
  • Biggest enclosure
    problem

    Biggest enclosure

    Age
    14 to 16
    Challenge level
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    Three fences of different lengths form three sides of an enclosure. What arrangement maximises the area?
  • Eyes Down
    problem

    Eyes down

    Age
    16 to 18
    Challenge level
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    The symbol [ ] means 'the integer part of'. Can the numbers [2x]; 2[x]; [x + 1/2] + [x - 1/2] ever be equal? Can they ever take three different values?
  • Approximating Pi
    problem

    Approximating pi

    Age
    14 to 18
    Challenge level
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    By inscribing a circle in a square and then a square in a circle find an approximation to pi. By using a hexagon, can you improve on the approximation?
  • Mediant madness
    problem

    Mediant madness

    Age
    14 to 16
    Challenge level
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    Kyle and his teacher disagree about his test score - who is right?
  • Plutarch's Boxes
    problem

    Plutarch's boxes

    Age
    11 to 14
    Challenge level
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    According to Plutarch, the Greeks found all the rectangles with integer sides, whose areas are equal to their perimeters. Can you find them? What rectangular boxes, with integer sides, have their surface areas equal to their volumes?
  • Unit Interval
    problem

    Unit interval

    Age
    14 to 18
    Challenge level
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    Take any two numbers between 0 and 1. Prove that the sum of the numbers is always less than one plus their product?
  • Giants
    problem

    Giants

    Age
    16 to 18
    Challenge level
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    Which is the bigger, 9^10 or 10^9 ? Which is the bigger, 99^100 or 100^99 ?
  • Inequalities
    problem

    Inequalities

    Age
    11 to 14
    Challenge level
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    A bag contains 12 marbles. There are more red than green but green and blue together exceed the reds. The total of yellow and green marbles is more than the total of red and blue. How many of each colour there are in the bag?