Which of the below owl is odd one out?

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

A chess tournament is taking place on knock-out terms (the one who loses the match is out of the game).
(a) If 10 matches are played in total, how many players participated?
(b) If 20 players took part in the tournament, how many matches were played?

What does below Rebus mean ?

esgg sgeg gegs gsge

A chicken farmer has figured out that a hen and a half can lay an egg and a half in a day and a half. How many hens does the farmer need to produce one dozen eggs in six days?

There was a blind man. He had four socks in his drawer either black or white. He opened it and took out two socks. Now the probability that it was a pair of white socks is 1/2.

Can you find out the probability that he had taken out a pair of black socks ?

A man is found dead in his bathroom naked with blood scattered all around him. The bathroom was locked from the inside and there is no trace of any struggle. There is nothing in the bathroom except his pant with the belt still around and his shirt. Also, the medic team can't find any incision in his body that may have been the reason behind so much blood loss.

The Police department is clueless regarding this murder mystery.
Can you?

You can hear me, but you can't touch or see me.

What am I?

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?