To find the theoretical probability of drawing a blue or yellow marble from the bag, we first determine the total number of marbles and the number of blue and yellow marbles.
The bag contains:
- 3 red marbles
- 2 blue marbles
- 5 yellow marbles
So, the total number of marbles is: \( 3 + 2 + 5 = 10 \) marbles.
Next, we find the total number of blue and yellow marbles: \( 2 \text{ (blue)} + 5 \text{ (yellow)} = 7 \) marbles.
Now we can calculate the probability of drawing a blue or yellow marble: \[ P(\text{blue or yellow}) = \frac{\text{Number of blue or yellow marbles}}{\text{Total number of marbles}} = \frac{7}{10}. \]
Thus, the theoretical probability of drawing a blue or yellow marble is \( \frac{7}{10} \) or 7 tenths.
So, the correct response is:
7 tenths.