Good Riddles

Question: A knight comes to a castle where his love is trapped. The castle is surrounded by a square moat that is 10 feet wide (it forms a square around the castle). The knight is able to fashion two 9 foot long planks to cross the moat.

How can he do this?

Question: Thousands of orphans who lost their old home,
found by others who have lost their own.
To hide a secret that is obvious to all,
becomes even more obvious when the host falls.

What am I?

Question: Alone I am 24th, with a friend I am 20. Another friend and I am unclean.What am I?

Question: At night they come without being fetched, and by day they are lost without being stolen.

What are they?

Question: A man challenges you to a coin flipping contest. One of you must flip heads, then tails, then heads. The other must flip heads, then tails, then tails. Whoever succeeds in fewer flips is the winner.

Which should you choose?