Move four matchsticks to the below square to form three squares?

Solve the below puzzle by replacing the question mark with the correct number.

3 6 12

4 8 16

5 10 ?

Three ants are sitting at the three corners of an equilateral triangle. Each ant starts randomly picks a direction and starts to move along the edge of the triangle. What is the probability that none of the ants collide?

In which direction should the missing arrow point?

Let's play a word game. Following are some meaningless words that can be completed by adding random letters on either side of the word.

For example, the word "rdo" can be formed into "pardon".

Using the same technique, can you complete the given words?
ecalc
airb
rinci
tibac
uidel
gorit
igna
eyho

You have two buckets of 11 liters and 6 litres.
How can you measure exactly 8 litres?

Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

How many triangles can you find in this given picture?

Using Only Five 5's and any mathematical operator make sum as 37

John went to meet his friend Jacob, but when he was about to reach the main gate, John notices that Jacob had a mighty dog who was fastened to the tree. The chain is long enough that it allows the dog to reach the main gate.

How can the John reach the main gate?