Find the next number in the series below

21 32 54 87 131 ?

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

You need to complete the maze by entering from the entrance marked below in the figure near the yellow circle, bottom left and leaving from the exit point near the green circle, bottom middle.

Rule of Game: You can move only by exchanging green and yellow circles.

Queen Elizabeth organised a royal party.

To Avoid uninvited guest royal family set a password.
Jack (an uninvited person) plan to enter the party. He stand nearby the door.

First guest comes, the security person said 'twelve' and guest replied with six.
Second guest comes , the security person said 'six' and guest replied with 'three'.

Jack thought is enough and he walked to the entry point. The security person said 'eight' , Jack replied smilingly 'four'.
He was immediately thrown out of the party. why ?

Decode the below four famous ciphers:

8P of the SS
1M of the E
1S of the SS
60M in 1H

I speak without a mouth, and hear without ears. I have no-body, but I come alive with the wind. What am I?

What is the next number in this series?

4,12,84,3612....

When monkey rotate the gear, which mark will be hit 1 or 2 ?

What is the centre of gravity?

No one wants to have it, but if one got it, he does not want to lose it. What is It?