What's the only room from which no one can enter or leave

Replace the question mark with the correct number.

2 + 2= 4
3 + 3= 18
4 + 4= 48
5 + 5= ?

A man and a dog were going down the street. The man rode, yet walked. What was the dog’s name?

Transform the word THINK into BRAIN while changing only one letter at a time in a manner that each of the word in the process is a real word!!!

Before the start of the car race, John and Jacob have the same amount of fuel in their car. With this fuel, John can drive for 4 hours while Jacob can drive five hours.
After a time they realize that the amount of fuel left in John's car is 1/4th of the fuel in Jacob's.

For how long they are racing?

Which is heavier: a ton of bricks or a ton of feathers?

You enter your friend's room. He is not in his room. Although you see that on the bed there are two dogs, five cats, two giraffes and three pigs. Also, a couple of chickens and ducks are flying in the room.

Calculate the number of legs standing on the floor.

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

Can you make a six-letter word using the letters N, A and B ?

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?