There is  more probability that Caleb will pick a Green Marble in random because these are the most in number.
To get the percentage of getting the probability of chance Caleb would get either red of black marble firstly is to get the total marble caleb have and divide it to the total of red and black marble, then lastly multiply it to 100 to get the percentage

1. Adding all different colour of marbles, Caleb will get 50 of total marbles all in all
2. Add ing the red marble (11 marbles) with black marbles (2 marbles) you will get 13 marbles in total
3. divide 50 with 13, you will get 0.26
4. multiply it to 100 to get the percentage, you will have 26%

the answer is:
There is a 26% chance of probability that Caleb will select in random either a red or a black marble.
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