Answer:
The total number of marbles in the bag is 4 + 12 + 8 + 2 = 26.
The probability of not picking a red marble out of the bag is equal to the number of marbles that are not red divided by the total number of marbles in the bag.
The number of marbles that are not red is 4 (blue) + 8 (green) + 2 (yellow) = 14.
Therefore, the probability of not picking a red marble out of the bag is 14/26 or 7/13.
So the probability of not picking a red marble is 7/13.