Answer:
18
Explanation:
We could test it out! (Just kidding)
But seriously, that could also be a method, because there are only so many two-digit multiples of nine.
Let's say the number is 10a+b,
then, 10a+b/3=10b+a/2 +3
Multiplying both sides by 6 gives us
20a+2b=30a+3b+18
10a+b=-18
Therefore, the answer is -18
Feel free to tell me if I did anything wrong! :)