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,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

Can you tell a 3D object that has just two surfaces?

Solve the mathematical equation in the picture below.

Can you count the number of seconds in a year?

Clue: You need to bother about calculation.

Replace the question mark with the correct number.

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

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

using four eights (8) and a one (1) and one mathematical symbol , create the number 100

Given that

(78)^9 = 6
And (69)^4 = 11

Can you find out

(99)^2 =?

(Note: This is Logical, not Mathematical)

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?