SOLUTION:
Step 1:
In this question, we are told that Charlie uses 3 times as much
Solution A as Solution B.
A = y
B = 3 y
Now, Solution A is 15% alcohol and Solution B is 10% alcohol and the resulting mixture has 330 milliliters of pure alcohol.
Step 2:
We have that:

Step 3:
Since the volume of solution B = 3y

CONCLUSION:
The volume of solution B = 2200 millimetres