6 purple, 4 blue, 10 green
"What is the probability that the marble picked will not be green?"
Well, simply all the purple and blue together :)
6 + 4 = 10
So, 10 marbles are not going to be green.
So, 10 green, 10 non-green.
So, our probability is 10 : 10
Which, simplified, is 1 : 1
~Hope I helped!~