Notice that the blank space asks for the probability of picking a brass bead, P(brass).
To find it, divide the number of times that a brass bead was chosen over the total amount of times that a bead was chosen.
Add the numbers from the table to find the total amount of times that the group of friends grabbed a bead:
Since a brass bead was chosen 72 times, the probablity of chosing a brass bead is:
Simplify the fraction by dividing the numerator and the denominator by the GCF of 72 and 300, which is 12:
Therefore, the probability of choosing a brass bead, is 6/25.