Answer:
11/17
Step-by-step explanation:
Probability = # of favored outcomes / total # of possible outcomes.
Favored outcomes: picking a red or yellow marble.
There are 8 yellow marbles and 3 red marbles. 8 + 3 = 11 so there are 11 favored outcomes.
There are 8 yellow marbles, 3 red marbles and 6 orange marbles. 8 + 3 + 6 = 17 so there are 17 possible outcomes.
The probability of pulling a red or yellow marble would be 11/17 because there are a total of 17 marbles in which 11 of those are red or yellow