The diagram shows six discs. Each disc has a colour and a number. Two of the six discs are picked at random without replacement. Find the probability that both discs have the same colour. .............................................

E8.5 Calculate the probability of simple combined events, using possibility diagrams, tree diagrams and Venn diagrams. (In possibility diagrams, outcomes will be represented by points on a grid, and in tree diagrams, outcomes will be written at the end of branches and probabilities by the side of the branches.)