Question

A bag contains 8 blue marbles, 6 green marbles, 12 yellow marbles, and 10 orange marbles. A marble is drawn at random from the bag.
What is the probability that the marble drawn will not be blue?

A. 2/9

B. 3/4

C. 7/9

D. 7/8

Answer 1

Probability of anything =

     (number of possible successful outcomes)
divided by
     (total possible number of outcomes) .

There are 36 total marbles in the bag, so there are 36 total
possible outcomes of one draw.

The successful outcomes are all the possible draws that are
not blue.    There are 28 of those.

So the probability of a non-blue selection is 

         28/36  =  7/9  =  77.8%  (rounded)