Answer:
11:30 PM
Step-by-step explanation:
This question is essentially asking for the lowest common multiple of 10, 20, and 30. If we write out all the multiples of each, we get:
10: 10, 20, 30, 40, 50, 60, 70, ...
20: 20, 40, 60, 80, ...
30: 30, 60, 90, ...
As you can see, the lowest common multiple is 60, and 60 minutes after 10:30 PM is 11:30 PM.
