Solve below rebus puzzle?

Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

I am a type of food that is often found in the fridge and can be white in colour. What I am?
Hint 1: I am a dairy product.
Hint 2: You can spread me on the bread.

When it is alive we sing, when it is dead we clap our hands. What is it?

A wooden log balances equally on the scales when weighed with three-quarters of a pound and three-quarters of a wooden log.

Can you calculate the weight of the entire wooden log?

On a windy rainy night , I was driving in my car.
When i reach the bus stand , i see three people waiting for the bus.

1. An old lady who needs an immediate medical attention
2. My Best Friend
3. Girl whom i love from childhood

My car is a two seat, so can you tell me , what i have done in this situation ?

Can you find out which options fits best with the missing column?

Teacher ask the student

'Why are you standing on that chair in music class ?'.

what did student replied ?

Find the next number in the series?
2, 12, 36, 80, 150, 252, 392, _ ?

Why Aeroplane windows are round?