Given:
Number of red marbles = 6
Number of orange marbles = 11
To find:
The theoretical probability of choosing a red marble.
Solution:
We have,
Number of red marbles = 6
Number of orange marbles = 11
Either we can select a red marble or orange marble.
Total types of marbles (Red and orange) = 2
So, the theoretical probability of choosing a red marble is:


Therefore, the theoretical probability of choosing a red marble is 0.5.