You have total 9 marbles. You have only 3 red marbles and 6 other colored marbles.
Now you are searching for a marble randomly picked and it is not red.
When you simplify,
or approximately 67 percent.
We have two options to solve this problem algebraically, I have listed both of them here.
Note that there are 6 non-red marbles and 9 total marbles, therefore the probability of selecting a non-red marble is
We can use complementary counting to find the probability of which the marble drawn is not red. (Complementary counting is frequently used to find the number of ways or probability of something NOT happening.)
First, we find the probability that the marble selected IS red then subtract it from
Since the total number of marbles in the jar is
Now, we can do