Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

We know that the number 7 is the prime followed by a cube. Which next number is also a prime followed by a cube?

There was a strange boy who was born before his father. How can this be possible?

What am I?

What goes up but never comes down?

Can you find the largest Three-digit number whose sum is 14 and whose square is less than 5,00,000?

Two old friends, Jack and Bill, meet after a long time.

Three kids
Jack: Hey, how are you, man?
Bill: Not bad, got married and I have three kids now.
Jack: That's awesome. How old are they?
Bill: The product of their ages is 72 and the sum of their ages is the same as your birth date.
Jack: Cool..But I still don't know.
Bill: My eldest kid just started taking piano lessons.
Jack: Oh, now I get it.

How old are Bill's kids?

A river should be crossed by a father, a mother and their two sons and two daughters.
There are some rules that should be followed while crossing the river. There can be only two people in the raft while crossing. The daughters cannot be with their father unless there is the presence of the mother. The sons cannot be with their mothers unless the father is present. Unless the guard is on the board, the criminals cannot be with any of the family members. Only the adults like the father, the guard, and the mother knows to use the raft.

How will they cross the river?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?