Combinations

  • Painting Cubes
    problem

    Painting cubes

    Age
    11 to 14
    Challenge level
    filled star filled star filled star
    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?
  • Coin Tossing Games
    problem

    Coin tossing games

    Age
    14 to 16
    Challenge level
    filled star filled star empty star
    You and I play a game involving successive throws of a fair coin. Suppose I pick HH and you pick TH. The coin is thrown repeatedly until we see either two heads in a row (I win) or a tail followed by a head (you win). What is the probability that you win?
  • Tetrahedron faces
    problem

    Tetrahedron faces

    Age
    7 to 11
    Challenge level
    filled star filled star filled star
    One face of a regular tetrahedron is painted blue and each of the remaining faces are painted using one of the colours red, green or yellow. How many different possibilities are there?
  • Teams
    problem

    Teams

    Age
    16 to 18
    Challenge level
    filled star empty star empty star
    Two brothers belong to a club with 10 members. Four are selected for a match. Find the probability that both brothers are selected.
  • Six is the Sum
    problem

    Six is the sum

    Age
    7 to 11
    Challenge level
    filled star filled star empty star
    What do the digits in the number fifteen add up to? How many other numbers have digits with the same total but no zeros?
  • Fair Exchange
    problem

    Fair exchange

    Age
    5 to 7
    Challenge level
    filled star empty star empty star
    In your bank, you have three types of coins. The number of spots shows how much they are worth. Can you choose coins to exchange with the groups given to make the same total?
  • problem

    The puzzling sweet shop

    Age
    5 to 11
    Challenge level
    filled star filled star empty star

    There were cola bottles for 2p, mini eggs for 3p, marshmallow twists for 5p and lollipops for 7p in the sweet shop. What could each of the children buy with their money?

  • Hubble, bubble
    problem

    Hubble, bubble

    Age
    7 to 11
    Challenge level
    filled star filled star empty star
    Winifred Wytsh bought a box each of jelly babies, milk jelly bears, yellow jelly bees and jelly belly beans. In how many different ways could she make a jolly jelly feast with 32 legs?
  • Delia's routes
    problem

    Delia's routes

    Age
    7 to 11
    Challenge level
    filled star filled star empty star
    A little mouse called Delia lives in a hole in the bottom of a tree.....How many days will it be before Delia has to take the same route again?
  • On Target
    problem

    On target

    Age
    7 to 11
    Challenge level
    filled star filled star filled star
    You have 5 darts and your target score is 44. How many different ways could you score 44?