Logic Riddles

Question: Who was buried in Grant's Tomb?

Question: A man and his son are in a terrible accident and are rushed to the hospital in critical care. The doctor looks at the boy and exclaims "I can't operate on this boy, he's my son!" How could this be?

Question: A man leaves his cabin and travels 100 meter north, 100 meters west, and 100 meters south just to arrive back at his home. He sees a bird. What kind of bird is it?

Question: To dye a single Easter egg takes 7.5 minutes if you leave it in dye. How long would it take to dye 3 eggs?

Question: A woman is in the hospital for a routine procedure. The doctor leaves the room locking the door before he goes, the woman is alone. The doctor comes back to find the woman has died and there is another person is in the room. The door was still locked.
How is this possible?