When my father was 31 I was 8. Now he is twice as old as me. How old am I?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

I look flat, but I am deep. Hidden realms I shelter. Lives I take, but the food I offer. At times I am beautiful. I can be calm, angry, and turbulent. I have no heart but offer pleasure as well as death. No man can own me, yet I encompass what all men must have. What am I?

How can you write nineteen in a manner that if we take out one, it becomes twenty?

Why is 6 afraid of 7?

I live in a bowl. I can swim. I have a tail. I also have fins and big eyes. What am I?

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?

In my garden, I have many trees but only one of them is the mango tree. In these mango trees, there are some mangoes(as expected).

But after a strong wind, there are neither mangoes on the tree nor on the ground. Explain?

It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

Which is the smallest number that you can write using all the vowels exactly once?