Question

Two discs are randomly taken without replacement from a bag containing 3 red discs and 2 blue discs. What is the probability of taking 2 red discs ?​

Answer 1

3/10

Explanation:

There are totally 5 disks. On the first pick, there are 3 red discs. So

P(red disc on first pick ) = 3/5

Assuming that a red disc has been picked the first time, there will be 2 red discs and 2 blue discs so

(P red disc on second pick given red disc on first pick) = 2/4

P(red disc on both picks) = 3/5 x 2/4 = 3/10