Given:
Total number of marbles = 15
Probability of randomly selecting a green marble = .
Probability of randomly selecting a green marble, replacing it, and then randomly selecting a blue marble = .
To find:
The number of blue marbles.
Solution:
Let the number of blue marbles be x.
It is given that,
Probability of randomly selecting a green marble, replacing it, and then randomly selecting a blue marble is . So,
Multiply both sides by 75.
Therefore, the number of blue marbles in the bag is 6.