Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

If your uncle’s sister is not your aunt, what relation is she to you?

I have a mouth but I don't eat.
I have a bank but have no money.
I have a bed but i dont sleep.
I wave but have no hands.

Who Am I ?

What is more useful when it is broken?

I am an eight letter word and I am a computer terminology.
The second, third and fourth letters make an animal.
The fourth, fifth, sixth, seventh and eighth letters make a weapon.
The first, second, third and fourth letters can be taken as an outcome of any exam.
The fifth, sixth, seventh and eighth letter combine to form a high end typing software.

Can you tell who am I ?

What can jump higher than a building?

Can you place six X (crosses) in below board without making three in a row in any way ?

Krish is 45 years old and his mother Crishtina is 73 years old.

Can you find out how many years ago, his mother was three times his age?

Can you replace the question mark with the correct number?

Which tank will fill first?