Question 572735
2 white marbles + 4 blue marbles + 6 red marbles = total of 12 marbles.


P(not blue) = 8 marbles (2 white + 6 red = 8) are not blue out of 12 total marbles 
P(not blue) = 8/12 


Reducing by dividing each side by 4 gives ... 
P(not blue) = 2/3