-5
I did that help? I hope I helped you
Answer:

Step-by-step explanation:
The number inside the square root symbol is the number you have to get when you multiply a certain number twice.
So
:
What multiplied by itself is 121?
Backwards equation:


Do not do the backwards method all the times, it does not work for all numbers.
Answer:
C, 15
Step-by-step explanation:
i looked it up
Answer:
It is most-likely a red marble
Step-by-step explanation:
I say it is a red marble because as you said, there are 10 red marbles and 6 blue ones and since there are 4 more red marbles, there is a higher perchentage of it being a red marble . (I hope i answered your question)