How can you make number one disappear by adding something to it?

What word is pronounced the same if you take away four of its five letters?

How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?

There is a box full of marbles,
all but two are blue,
all but two are green,
and all but two are red.

How many marbles are in the box?

You find yourself in a strange place guarded by two guards.One of the guard always say truth while other always lies.You don't know the identity of the two.You can ask only one question to go out from there. What should you ask?

It's a protector.
It sits on a bridge.
One individual can see directly through it, while others wonder what it hides.

What is it?

What does this below rebus puzzle mean?

John is the son of Jacob.
So,
Jacob is the_____of John's father?

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

Two fathers and two sons went fishing one day. They were there the whole day and only caught 3 fish. One father said, that is enough for all of us, we will have one each. How can this be possible?