Find the next number in the sequence

5 12 24 36 ?

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

I never was there, I am always to be.
You have never ever seen me, not ever you will.
Yet I am the confidence of everyone.

Who Am I?

What does the following represent?

N N N N N N N

A A A A A A A

C C C C C C C

What have one eye but still cannot see?

If eleven plus two equals one, what does nine plus five equal?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

A pet show was happening in my locality. I went down along with my kids. In that show, I noticed that all except two of the entries were cats. All except two were dogs and all except two were Monkeys.

Can you find out how many of each animals were present in that pet show?

A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?