What work can one never finish?

ENEMY = 2 * LINK
LINK + 2 = HELL

Then what will be TAXI + HELL? Select from the options below:
a) ROTTEN
b) DANGER
c) HEAVEN
4) MORTAL

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

Why do you find that most of the buildings are deprived of the 13th floor?

The following four words might seem abrupt to you. But you can make them meaningful by just adding vowels.
RDSH
GGPLNT
TMT
NN

Hint: All of them are vegetables.

Complete the table series riddle by finding the number that can replace "??".

Solve the following series:
AZ, GT, MN, __, YB

Identify the movie name through below Rebus containing Pi Mouse and coconut tree..

My first is in chocolate but not in ham. My second is in cake and also in jam. My third at tea time is easily found. Altogether, this is a friend who is often around. What is it?