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?

If an electric train is travelling south, then which way is the smoke going?

Considering the below equation:

V + II - VI = 10
IV - X + VIII = 20
IV - VII + VI = 30

Then, I + II + III = ?

Two old friends, Jack and Jill, meet after a long time, and discussing as:

Jack: Hey, how are you, man?

Bill: Not bad, got married and I have three kids now.

Jack: That's awesome. How old are they?

Bill: The product of their ages is 72 and the sum of their ages is the same as your birth date.

Jack: Cool..But I still don't know.

Bill: My eldest kid just started taking piano lessons.

Jack: Oh, now I get it.

How old are Bill's kids?

Solve the following series:
AZ, GT, MN, __, YB

John’s parents have three sons: Snap, Crackle, and what’s the name of the third son?

What is common among 11, 69, and 88?

Here is a mathematical expression that also secretly tells a movie name. What movie is that?

We know that the number 7 is the prime followed by a cube. Which next number is also a prime followed by a cube?

What has many teeth, but cannot bite?