Good Riddles

Question: A young man walks through the forest. He comes to a bridge. In front of the bridge is a large man carrying an axe. The man says, "If you want to cross this bridge, you must tell me a statement. If I think the statement is true, you will be strangled to death. If I say the statement is false, your head will be chopped off." A few minutes later, the young man walked over the bridge, while the larger man stood pondering. What was the statement the young man had given?

Question: Use the numbers 2, 3, 4 and 5 and the symbols + and = to make a true equation.

Note: Each must be used exactly once and no other numbers or symbols can be used.

Question: What goes on four legs in the morning, on two legs at noon, and on three legs in the evening?

Question: Some use me, while others do not.
Some remember, while others have forgot.
For profit and gain I'm used expertly, I can't be picked off the ground or tossed in the sea.
Only gained through patience and time, can you unravel my rhyme?

Question: I go into the water red and come out black.

What am I?