Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

People make me, save me, change me, raise me. What am I?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

In a stable, there are men and horses. In all, there are 22 heads and 72 feet. How many men and how many horses are in the stable

You have an empty wine bottle with a cork that has been secured at the top in a normal way. There is a metal ring inside the bottle that is suspended by a string.

How can you make the metal ring drop to the bottom if you are not allowed to touch anything - not the bottle, not the cork, not the thread and not the ring?

As a whole I am both
safe and secure.

Behead me and I become
a place of meeting.

Behead me again and I am
the partner of ready.

Restore me, and I become
the domain of beasts.

What am I?

Doctor Alex and a bus driver John are both in love with the same woman named Olivia. The bus driver need to go for a long trip of 10 days, Before he left he gave Olivia 10 apples.

What do you call a fish without an eye?

Make the seating arrangement of 10 children in such a way that there are 5 rows with 4 children in each row.