Take the number of pen per box and multiply by the number of boxes giving you the total number of pens bought
For this case we have that by definition, the GCF (Greatest Common Factor) is the largest integer that divides the numbers.
We have the following expressions:

We find the factors of 9 and 6:

Thus, the largest number that divides 9 and 6 is 3
It is also observed that "b" is the common variable of both expressions
Therefore, the GCF of the expressions is:

Answer:

Total number of marbles=5+3+4=12
Probability of picking a red marble =5/12
Answer:
1/3 in decimal format is .333333333333... so none of these are correct