If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

What is the next number in this series?

4,12,84,3612....

In the picture given below, can you find out which digit will take place of the question mark?

The following sentence is false. The preceding sentence is true.
Are these two sentences true or false?

Which of the eight images will fill the missing image in the puzzle below?

We have shown you a regular water barrel as below. Without using any measuring device can you check if the barrel is more than half-filled or less than half-filled?

Find the missing number in the image below.

As you can see that fifteen matches have been used to form an arrangement. What you have to do is remove any six of them to make them ten.

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

Two Twins Jack and Jill were standing back to back and suddenly they started running in opposite direction for 4 kilometres and then turn to left and run for another 3 kilometres.

what is the distance between the Baggio twins when they stop ?