What work can one never finish?

A person is found murdered in his Chamber. When the crime scene is investigated, the Investigator find out that there is a calendar on which the victim has written a few numbers with his blood. The numbers are 4, 11, 11 and 4.

There are four suspects in the murder, John, Jacob, Anna and Lee. Can you find out who is the murderer?

You have a roll of cloth 1km long. You have a machine which cuts this roll into pieces of 10-meter-long cloth.

How long would it take for the machine to cut the roll if each cut took 4 secs?

Can you decipher the following common phrase?

T M C
A U O
H S M
W T E

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

What am I?

What does this rebus means ?

PROG WORKRESS

What Adam and Eve do not have but the rest of the people have?

What do you answer even though it never asks you questions?

Prove that twice of ten is the same as twice of eleven.

What is the longest word in the dictionary?