Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?

O_er_t_o_

Complete the missing letters of the given word.

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

Which is heavier: a ton of bricks or a ton of feathers?

I am thinking of a five-digit number such that:
The first and last digits are the same, their submission is an even number and multiplication is an odd number and is equal to the fourth number. Subtract five from it and we obtain the second number. Then divide into exact halves and we get the 3rd number.

What number I am thinking of?

How many triangles are there on the puzzle below?

I was speeding and ran through a stop sign, yet two traffic officers who were there do nothing about it.

why?

There are five vowels (a, e, i, o, u) in the English language.
Can you tell us a word that contains all these vowels?

Can you name four days which start with the letter 'T'?