Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

Something Extraordinary happened on May 6th 19778 at 12:34am what was that?

What Does this text mean:

important=important

What have one eye but still cannot see?

What does does this rebus picture means ?

I am the fastest animal but cannot climb the tree. What am I?

An American nightclub called 'The Coconut Grove' had a terrible fire in which over 400 people died. A simple design flaw in the building led to a high death toll. Subsequently, regulations were changed to ensure that all public buildings throughout the country eliminated this one detail, which proved deadly. What was it?

A detective visits his friend John just to discover that John's neighbour Dr Jacob was murdered. Dr Jacob, who is a mathematician wrote the murderer's name in a code word "Hcqtfz". There were five suspects
1. Ajit
2. Pankaj
3. Ganpat
4. Deenu
5. Hariya

The Detective was instantly able to find the murderer.
Can you?

Decode below rebus
D
N
A
T
S , D

O_er_t_o_

Complete the missing letters of the given word.