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 are on a Boat in the mid of a river. You have two cigarettes with you. One of these two you have to light, how will you light the cigarette?

If 21x = 79x, what is the value of x?

What is the coolest letter in the alphabet?

Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.

If all the below statements are true

1. Gianni was either in Italy or France in 1997.
2. If Gianni did not kill Versace, Hilton must have killed him.
3. If Versace died of suffocation, then either Gianni killed him or Versace committed suicide.
4. If Gianni was in Italy in 1997, then Gianni did not kill Versace.
5. Versace died of suffocation, but he did not kill himself.

Who killed Versace and where was Gianni in 1997?

What is next number in the pattern below:

131 517 192 123 ?

Can it be possible to build a house that has all its four walls facing towards the South?

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

Below, you can see some coding:
January = 1017
February = 628
March = 1335
April = 145
May = 1353
June = 1064
July = 1074
August = 186

Now deciphering the way it has been coded, can you find out how September will be coded?