What work can one never finish?

A deaf and mute man goes to the train station. Tickets for the train are 50 cents each. The man goes to the ticket booth and hands the man inside just a dollar. The man in the booth hands him two tickets.

How did the man in the booth know to give him two tickets without even looking at him?

A boy and a girl are sitting on the porch.
"I'm a boy," says the child with black hair.
"I'm a girl," says the child with red hair.
If at least one of them is lying, who is which?

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

Find three whole, positive numbers that have the same answer when multiplied together as when added together.

A bag contains 64 balls of eight different colours. There are eight of each colour (including red). What is the least number you would have to pick, without looking, to be sure of selecting 3 red balls?

Can you find the odd number in the following?

2716, 4135, 5321 and 7145

Get total of 120 by using five zeros 0,0,0,0,0 and any one mathematical operator.
Do you ?

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

Why 1729 is a magic number? Answer Logically.