Logic Riddles

Question: If it takes three men two days to dig a hole, how long does it take one man to dig half of a hole?

Question: You are a surgeon who has to perform 3 operations today, but you only have 2 pairs of gloves (a and b) to perform the operations. Each of the people you are performing surgery on are infectious so you cannot touch any of them or their bodily fluids and they can't touch each other's bodily fluids. How do you perform all 3 operations with only 2 pairs of gloves?

Question: What single line can you add to the following statement to make it true?

5+5+5=550

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?

Question: How can you make a TV, a bed, a dog, and a car liquid?