Good Riddles

Question: You have found a mutant algae that doubles in size every hour. It takes 18 hours for one algae plant to take up half of a certain lake.

How long would it take for two of these plants to take up half of the same lake?

Question: What did the tree say to the wind

Question: I rule the ends of the universe. I control its laws. I reign the galaxy. The start of space is the start of me. The end of the universe is the end of me. The name of my slaves bring mighty terror to you. The universe wouldn't work if it wasn't for me. What am I?

Question: The more you cut into me the bigger I grow, what am I?

Question: There are ten horses in a field. They each have a stable. There was a storm one day and struck one of the stables. The stable burned. There are now 9 stables. Every horse has to go in a stable at night. You can't build another stable and you can't fit 2 horses in one stable. How do you fit ten horses in 9 stables?