What work can one never finish?

There was a man he lives in a hotel each morning he presses the first floor button each evening if there is a person in the elevator he asks him to press the 10 floor button if there is no one in the elevator he takes the stairs why.

John named his first son Alpha, second Beta, third Charlie and fourth Delta. What is the fifth son's name?

Jenifer and Jesica are having a conversation.

Jenifer: I am definitely not over 30.
Jesica: I am 28 and you are surely 5 years older to me at least.
Jenifer: No, you are at least 29.

You are told that both of them are lying throughout in the conversation. Can you find their respective ages?

As shown in the image, the nine Dogs are square fenced. By constructing just two square fences can you make sure that two Dogs cannot meet each other without crossing the fence?

If,

20 % 5 = 24

21 % 7 = 33

42 % 6 = 67

Then;

66 % 6 = ?

If you say my name, I will no longer exist. What am I?

If it took eight men ten hours to build a wall, how long would it take four men to build it?

I know a country, If you remove the last alphabet of its name, it will become a part of your body. Do you name it?

I am the beginning of everything, the end of everywhere. I'm the beginning of eternity, the end of time and space. What am I?