Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

What does this rebus mean?

O
N
C
E
TIME

The Little ant seems to be always confused. Do you know why?

What has hands, but can’t clap?

On a special event at the prison, 5 prisoners John, Jacob, Krist, Tang, and Dang given a chance to go to a sauna and can bring one thing with them.

Following are the things that the prisoners bring with them.
John: A soda
Jacob: Thermos
Krist: Book named "How to kill"
Tang: A Walkman
Dang: Harmonica

Since it is a Sauna, no one can see each other. After a while When the steam is switched, Tang was found dead and there was blood all around.
J Bond was called and he instantly come to know who can be the murderer. How?

Which of the following words don't belong in the group and why?
CORSET, COSTER, SECTOR, ESCORT, COURTS

A bomb exploded in a room full of married couples and no one died. How?

Why do we preferably have round manhole covers and not square ones?

What word begins and ends with an E, but has only one letter?

John is 45 years older than his son Jacob. If you find similarities between their ages, both of their ages contain prime numbers as the digits. Also, John's age is the reverse of Jacob's age.

Can you find their ages?