I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

I am a white box having no key or lid.
Yet there is a golden treasure inside it.

What Am I?

I am a type of food that is often found in the fridge and can be white in colour. What I am?
Hint 1: I am a dairy product.
Hint 2: You can spread me on the bread.

I know there are two methods by using three time the same number with a plus(+) operator , you can make sum as 60.

One of them is 20+20+20.

whats the other way ?

Why 1729 is a magic number? Answer Logically.

If a wheel has 54 spokes, how many spaces are there between the spokes?

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.

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

Explain?

I am white when I am dirty, and black when I am clean. What am I?