What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

With the help clues provided in the image, can you find the 5 digit key?

A boy was at a carnival and went to a booth where a man said to the boy, "If I write your exact weight on this piece of paper then you have to give me $50, but if I cannot, I will pay you $50." The boy looked around and saw no scale so he agrees, thinking no matter what the carny writes he'll just say he weighs more or less. In the end the boy ended up paying the man $50. How did the man win the bet?

Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?

It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

There is an English word that can be used up to four times in a row without modifying the spelling and form a valid grammatical sentence.

Do you know what word is that?

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

You order chicken wings at KFC in the boxes of 6, 9 and 20. What is the largest number of wings that you cannot obtain by buying in any combination of the boxes?

How can you write nineteen in a manner that if we take out one, it becomes twenty?

Rearrange the letters in "new door" to make one word.