Buy me, smell me or deliver me, I do not change.

Who am I?

Can you find the missing number in the third row?
35 20 14
27 12 18
5 2 ?

Every words stands for unique digit that makes the arithmetic equation true

SEVEN + SEVEN + SIX = TWENTY.

What are the digits ?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

What numbers should go on the bottom line?
3 6 9 15
8 2 10 12
11 8 19 27
19 10 29 39
? ? ? ?

Without looking at a calendar, within a minute name, a boy's name using 5 consecutive 1st letters of 5 consecutive months

How many sides does a circle have?

There is something which you can be arrested for attempting but not for successfully completing.

What brings you down but never up?

Why is it against the law for a man living in Delhi to be buried in Mumbai?