Abag contains 3 green marbles, 7 blue marbles and 2 black marbles. the probability of randomly picking a green marble is 1/4. what is the probability of not picking a green marble. show your work.

The probability of not picking a green is 3/4. To get this answer you would add up the blue and black marbles, giving you an answer of 9. You would then put 9 over 12, which simplified would equal 3/4. Another way to find the answer is to take 1 and subtract 1/4 because 1/4 is the probability of green marbles. Hope this helps :) 

Im not really sure if you add or something is that all it says