Q:A bag contains 5 black socks and 4 white socks. If 2 socks are picked randomly from it, find the probability of them being of the same colour.
What I've done is this:
probability of first sock being black: 5/9
probability of first sock being white: 4/9
Probability of both being black is therefore, 5/9 * 5/9 = 25/81
- Probability of both being black is therefore, 4/9 * 4/9 = 16/81
And probability of any 2 socks being of the same color is then: 25/81 + 16/81
I dont think what I've done is right. How would this be done?