I know the probability is about .63 because I found the probability of not choosing a blue marble, which is the same as finding the probability of choosing a red, green or yellow marble. There are 4 red marbles, seven green marbles and 6 yellow marbles. There are 10 blue marbles. I knew there was 27 marbles in all, so I found the probability of choosing a red, yellow or green marble.
4+7+6
_____ = 17/27 ~ 0.62962962963
27
In conclusion, the probability of the event of not choosing a blue marble is about .63 or 17/27.
Since there are 10 blue marbles, and 27 total marbles, the probability of not choosing a blue marble is 17/27 because you subtract the amount of blue marbles (10) from the amount of total marbles (27).