The probability of an event is expressed as
Given:
The probability of drwing two blue balls one after the other is expressed as
For the first draw:
For the second draw, we have only 1 blue ball left out of a total of 6 balls (since a blue ball with drawn earlier).
Thus,
The probability of drawing two blue balls one after the other is evaluted as
The probablity that none of the balls drawn is blue is evaluted as
Hence, the probablity that none of the balls drawn is blue is evaluted as