There are 4 white balls 5 blue balls and 3 green balls in a box 2 balls are chosen at random What is...........

Explanation:

Both balls being non-blue means both balls are either white or green
There are total 12 balls (4+3+5)
and total 7 white + green balls.
So required probability = ⁷C₂/¹²C₂ = [(7*6/2*1) / (12*11/2*1)] = 21/66 = 7/22

Hence, option 4 is the correct answer.