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?

Replace the question mark with the correct number.

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

The centre of the third figure is empty. What digit should fit inside?

A four-digit number (not beginning with 0) can be represented by ABCD. There is one number such that ABCD=A^B*C^D, where A^B means A raised to the B power. Can you find it?

Prove that twice of ten is the same as twice of eleven.

Imagine you are in a room with no windows or doors. How will you get out?

What is the largest number you can write with just 3 digits?

This is a simple one. You just have to count the number of Fs in the given sentence.

Finished Files are the result of years of scientific study combined with the experience of years.

How many did you count?

How many cubic feet of dirt are in a hole of one foot deep, three feet long, and two feet wide?

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?