Logic riddles

A man died and went to Heaven. There were thousands of other people there. They were all naked and all looked as they did at the age of 21. He looked around to see if there was anyone he recognised. He saw a couple and he knew immediately that they were Adam and Eve.
How did he know?

Answer

He recognized Adam and Eve as the only people without navels. Because they were not born of women, they had never had umbilical cords and therefore they never had navels.

"Life's funny", said an old friend when I bumped into him the other day. "Listen to this, I was born in March, yet I celebrate my birthday in August, and last February I married my mother".
How is this possible?

Answer

He was born in August in a town called March, became a priest and married his widowed
mother to her second husband in February

I start with M and end with X. I have a never ending amount of letters.
What am I?

Answer

A mailbox.

Imagine there are 3 coins on the table. Gold, silver and copper. If you say a truthful sentence, you will get one coin. If you say a false sentence, you get nothing.
Which sentence can guarantee gaining the gold coin?

Answer

"You will give me neither copper nor silver coin." If it is true, then I have to get the
gold coin. If it is a lie, then the negation must be true, so "you give me either copper or
silver coin", which would break the given conditions that you get no coin when lying.
So the first sentence must be true.

What word is pronounced the same if you take away four of its five letters?

Answer

Queue.

A box without hinges, key, or lid,
Yet golden treasure inside is hid.

Answer

Eggses

I start with 'e', end with 'e' but have only one letter.
What am i?

Answer

Envelope.

If two’s company, and three’s a crowd,
what are four and five?

Answer

Nine.