Logic Riddles

Question: In a town their is a barber who cuts everybody in the town's hair. But nobody in the town cuts their own hair. Yet the barbers always has beautifully kept and full hair.

Who cuts the barber's hair?

Question: You are surrounded by a 100 foot wide and 100 foot deep moat. You have a 40 foot tall ladder, matches, a gallon of water, and as much rope as you need.

How can you get across the moat?

Question: What is 1/2 of 2/3 of 3/4 of 4/5 of 5/6 of 6/7 of 7/8 of 8/9 of 9/10 of 10,000?

Question: When is 1500 plus 20 and 1600 minus 40 the same thing?

Question: I'm number three.
But I'm not a number.
I'm hot and cold at the same moment but not at the same time.
I'm number three.
But I'm not a number.

Who or what am I?