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?

What does this mean?

CCCCCCC

What English word has three consecutive double letters?

If 24H in a D => 24 hours in a day.
What does "64S on CB" stand for?

If it took eight men ten hours to build a wall, how long would it take four men to build it?

Can you divide the below-given shape into four equal and identical pieces?

In the given figure, you can see that four match sticks are used to form a square. Can you form five squares by using six matches?

Rearrange the letters in "new door" to make one word.

A network of 20 x 10 squares is given to you.

Can you calculate how many unique squares and rectangles can be formed combining two or more individual squares ?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211