How many times can you subtract the number two from the number fifty?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

Do You See It?

I am dry when I go inside, but wet when I am pulled outside.
The longer I am inside, the stronger I get
When I am completely out, I am wet and I literally sag
Who am I?

Which Burger Is Different in below image?

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?

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?

I am a five-letter word and comprises two different vowels and three same consonants. I am so strong that I can spoil your entire work.

Can you find out who am I?

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

Two in a corner, one in a room, zero in a house, but one in a shelter. What is it?