Answer: 11
Step-by-step explanation:
We start with x = 15 as shown in the first line.
The second line says "repeat the stuff in the curly braces until we reach x = 11". So either we reach x = 11 and that's our answer, or we're stuck in this loop infinitely. Luckily, it only takes one step to get out of this loop since 15-4 = 11. I subtracted off 4 because of the stuff in the curly braces.
So because we reach x = 11, we're able to break out of the loop and the program will display 11 as the final answer. The value 15 is never shown on screen to the user. So if they don't have access to the code, then they'll never see "15".