Math Riddles

Question: Two spies want to get in an enemy's military base. In order to get in they have to give the correct countersign to the guard at the gate after he gives them the sign. So, they wait hidden nearby the gate so that they will overhear the countersign from another soldier. One soldier comes and the guard gives the sign: "6". The soldier answers "3". The guard lets him pass. Another soldier comes. The guard says "12" and the soldier gives the answer "6". The guard lets him pass. So, the first spy goes at the gate and the guard says "10".The spy, sure that he knew the answer as he was, says "5". Immediately, the guard shoots him dead. Then the other spy, who saw that the other spy was killed when he gave the countersign, had now understood what the right answer would be, whatever the guard's sign was.So, he walks to the gate and the guard says "8".The spy gives the correct answer and the guard lets him in. What was the answer that the spy gave?

Question: Sam has two sons named Nathan and Daniel, Daniel is exactly 5 years older than Nathan and Daniel was born on February 29th 1996. How old is Nathan?

Question: Everyday a peasant must pay the king one pound of gold and leave it on a collection plate in front of his house. Every morning a guard comes by to make sure he has put a pound of gold on the plate. The king collects the gold every six days from the plate. If the peasant only has one six pound block of gold, how can he make only two parallel cuts and still follow the kings rules each day?

Question: If 4+5=24 7+2=21 9+6=63 6+7=?

Question: You have two buckets: one with only white marbles and one with only black marbles. The two buckets have the same number of marbles.

How can you rearrange the marbles to maximize your chances of grabbing a white marble from each?