Diophantine equations

  • Coffee
    problem

    Coffee

    Age
    14 to 16
    Challenge level
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    To make 11 kilograms of this blend of coffee costs £15 per kilogram. The blend uses more Brazilian, Kenyan and Mocha coffee... How many kilograms of each type of coffee are used?
  • 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?
  • Fibs
    problem

    Fibs

    Age
    11 to 14
    Challenge level
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    The well known Fibonacci sequence is 1 ,1, 2, 3, 5, 8, 13, 21.... How many Fibonacci sequences can you find containing the number 196 as one of the terms?
  • Double Angle Triples
    problem

    Double angle triples

    Age
    16 to 18
    Challenge level
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    Try out this geometry problem involving trigonometry and number theory
  • Our Ages
    problem

    Our ages

    Age
    14 to 16
    Challenge level
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    I am exactly n times my daughter's age. In m years I shall be ... How old am I?
  • Code to Zero
    problem

    Code to zero

    Age
    16 to 18
    Challenge level
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    Find all 3 digit numbers such that by adding the first digit, the square of the second and the cube of the third you get the original number, for example 1 + 3^2 + 5^3 = 135.
  • Exhaustion
    problem

    Exhaustion

    Age
    16 to 18
    Challenge level
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    Find the positive integer solutions of the equation (1+1/a)(1+1/b)(1+1/c) = 2
  • Some Cubes
    problem

    Some cubes

    Age
    16 to 18
    Challenge level
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    The sum of the cubes of two numbers is 7163. What are these numbers?
  • BT.. Eat your heart out
    problem

    BT... eat your heart out

    Age
    16 to 18
    Challenge level
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    If the last four digits of my phone number are placed in front of the remaining three you get one more than twice my number! What is it?

  • Rudolff's Problem
    problem

    Rudolff's problem

    Age
    14 to 16
    Challenge level
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    A group of 20 people pay a total of £20 to see an exhibition. The admission price is £3 for men, £2 for women and 50p for children. How many men, women and children are there in the group?