What number comes next in the series?

5 15 5 18 5 24 14 20 _

John and Jacob are twin brothers. One of them is a liar whereas the other one is a truth-teller.

I called their home number and one of them picked up.
I asked. 'Does John lie?' The person replied with a yes.

Whom did I talk with, John or Jacob?

Baseball bat and ball cost $100. If the bat cost $99 more than the ball, what is the cost of each?

Cristina was born in 1888. She just had her 30th birthday today how did that happen?

Spot 5 differences in two Christmas tree below:

What breaks yet never falls, and what falls yet never breaks?

I am a type of room you cannot enter or leave. Raised from the ground below, I could be poisonous or a delicious treat. What am I?

There was a kingdom in which the king had no heir to take over his thrown. Even the queen was dead and he himself was on the verge of dying. He thought about it and then summoned all of the teenagers. He gave one seed each to all of them and asked them to grow the plant. He announced that the one with the most beautiful plant will become the king/queen of the empire after the death of the king.

After a month, all of them were called. The king looked at all of the plants but announced the girl with an empty pot as the queen of the empire. Why?

Which tank will fill first?

When it's bad luck to meet a black cat?