Love For MathCreative Math Education

DIY Challenge 4: 25 horses Challenge

What if we had 25 horses?

How many races would you need to find the 3 fastest horses?

What students worked out5

  • Student 3

    race no 1
    a5a4a3a2a1

    race no 2
    b5b4b3b2b1

    race no. 3
    c5c4c3c2c1

    race no 4
    d5d4d3d2d1

    race no 5
    e5e4e3e2e1

    respective winners are a1b1c1d1e1

    so a4a5b4b5c4c5d4d5e4e5 are out of competition

    • Student 3

      race no 6
      a1b1c1d1e1

      say b1 wins (first position)

      then a3c3d3e3 are out of race

      • Student 3

        race no 7
        a1b2c1d1e1
        say b2 wins(second position)

        a2c2d2e2 are out of competition

        • Student 3

          race no 8
          a1b3c1d1e1

          say b3 wins (third position)

          so total 8 matches required

  • Student 2

    first 5 races
    row 1
    row 2
    row 3
    row 4
    row 5
    eliminate the last 2 in all races
    15 left
    first, do 3 races
    row 1
    row 2
    row 3
    the last 2 in all races are eliminated
    then we are left with 9
    we race any 5
    last 2 eliminated
    7 left
    then we race 5
    last 2 eliminated
    5 left
    then we race those 5
    last 2 eliminated
    the 3 left 1/2/3 this is the order these are the 3 fastest
    total of 11 races
    (if after 15 left is is sounded a Student 58 weird that is because i copy pasted from DIY-2