7. For the number $\overline{1 x 33 y}$, determine the digits $x$ and $y$ so that the number is divisible by 15.
7. A natural number is divisible by 15 if it is divisible by both 3 and 5.

Therefore, $y$ must be 0 or 5.

When the digit $y=0$, the digit $x$ can be 2, 5, or 8 4 points (since $1+3+3=7$).

When the digit $y=5$, the digit $x$ can be 0, 3, 6, or 9 4 points (since $1+3+3+5=12$).