Let's sum these two numbers.
8 + 31 = 39 total hours.
In every 12-hour the clock format changes AM to PM or the opposite PM to AM. So we need to divide 12 with the result 39.
There are 3 times 12 number in the 39
If the result is ODD number the time format will change the opposite side. If the result is EVEN number the time format will be the same.
Answer :3am
What is 31 hours from 8pm ? = 3am.
Add 31 hours to 8pm is equal 3am.