Find the next number in the sequence

5 12 24 36 ?

A doctor and a boy were fishing. The boy was the doctor’s son, but the doctor was not the boy’s father. Who was the doctor?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

Keyboard words are not in alphabetical order, Why?

Find the missing letter in the last circle logically in the given below picture.

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?

Replace the question mark with the number below given a simple math problem.

While going to your grandmother's house, you counted Twenty houses on the right side. While returning back to your home, you counted Twenty houses on the left side.

How many houses are there between your home and your grandmother's home?

Can you find out what is missing?

1 3 5
2 4 ?

Hint: It's not six. Think out of the box.

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