There are only (n +1) black buttons and (n-1) white buttons in a tin. Salma takes at random two buttons from the tin. Work out the probability that both buttons are white.
There are only (n +1) black buttons and (n-1) white buttons in a tin. Salma takes at random two buttons from the tin. Work out the probability that both buttons are white.
what have you tried so far / what are your thoughts?