You are presented with three boxes. One of them has a red ball inside and the other two have a black ball inside each of them. You are asked to pick up the one with red ball and you pick one. Now, one of the other boxes is opened and it is found to have a black ball.

You are presented with a chance to change your box with the one that is left closed. Will you change your box? Why or why not?

A father's child, a mother's child, yet no one's son.

Who am I?

John and Jenni are a married couple. They have two kids, one of them is a girl. Assume safely that the probability of each gender is 1/2.
What is the probability that the other kid is also a girl?

Hint: It is not 1/2 as you would first think.

With pointed fangs I sit and wait; with piercing force I crunch out fate; grabbing victims, proclaiming might; physically joining with a single bite. What am I?

Using Only Five 5's and any mathematical operator make sum as 37

If your uncle’s sister is not your aunt, what relation is she to you?

No one wants to have it, but if one got it, he does not want to lose it. What is It?

By using 'because' continuously three times, can you make an English statement ?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see? What is it?

If EELS + MARK + BEST + WARY = EASY

What does HELP + BARK + WARD + LEAD equal?