To solve this problem, you can set up an equation using the given information.
Let Z be the percentage of y that is equal to 18% of x.
Then:
(12/100) * x = (6/100) * y
(18/100) * x = (Z/100) * y
(9/5) * (6/100) * x = (Z/100) * y
Z = (9/5) * 6
Z = 9
Therefore, 9% of y is equal to 18% of x.