Answer:
Hey there!
To solve this problem, we must first find the total amount of time it takes for you to get ready in the morning!
20 minutes for shower + 15 minutes to eat + 10 minutes to walk.
This is a total of 20+15+10 or 45 minutes.
For our answer, we have that you should wake up 45 minutes before 11:15, which is 10:30 AM.
Let me know if this helps :)