A bag contains 12 discs

7 are red

3 are blue

2 are yellow

Two discs are taken from the bag at random, without replacement. Work out the probability that the two discs are the same colour. Please help :)

If they are both red, 7/22

If both blue, 1/22

Yellow, 1/66

Step-by-step explanation:

7/12 times 6/11 (both decrease by one because there is no replacement)

3/12 times 2/11

2/12 times 1/11

1) 2/5

2) zero=0/1

3) zero=0/2

4) -4/5

5) undefined=3/0