or
or
Given: 2 green and 2 red marbles
Required: Probability that 2 marbles picked both are red
Initially we have to pick 1 red from a total of 2 green and 2 red marbles = 2/4
After one red has been picked, we need to pick 1 red from a total of 2 green and 1 red marbles = 1/3
P(Both red) = (2/4)*(1/3)
= 2/12
= 1/6
