What does below chemistry rebus means?

Which tank will fill first?

A container contains 100 eggs. They can be either fresh or rotten. What is sure is the fact that there is at least one fresh egg in that container.

If you are asked to pick two eggs randomly from the container, at least one of them will be rotten.

Can you calculate how many eggs in that container are fresh?

What has a bottom at the top?

Solve The below Equation:

ALFA + BETA + GAMA = DELTA

Solve the rebus riddle in the picture below.

A girl was sitting in her hotel room when she heard a knock on the door. She opened the door and found that a man was standing outside. The man said, "Oh! I am really sorry, I thought this was my room." He then walked through the corridor to the elevator. The girl did not know the man. She closed her door and called security asking them to apprehend the man. What made her suspicious of that man? He might have been genuinely mistaken.

In the picture given below, can you find out which digit will take place of the question mark?

Can you place three balls such that the equation shown in the picture holds true?

Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?