Can You Answer These Standard Puzzles?

1.Racing Horses - There are 25 horses in a racing competition. You can have race among 5 horses in a particular race. What would be the minimum number of races that will be required to determine the 1st,2nd and 3rd fastest horses?

2.A 100 doors: You have 100 doors in a row that are all initially closed.You make 100 passes starting with the  first door every time. First time through you visit every door and toggle the door(if the door is closed,u open it,if it's open, you close it). The second time you only visit every 2nd door( door #2,#4,#6).The third time, every 3rd door(door #3,#6,#9), etc, until you visit only visit the 100th door.What state are the doors in after the last pass or in general after n pass?

3.The light bulb problem: You have three light bulbs in a sealed room.You know that initially,all three light bulbs are off.Outside the room there are three witches with a one-to-one correspondence to the light bulbs.You may flip the switches however you like and you may enter the room once.How should you flip the switches to determine which controls which light bulb?

4.Dropping Eggs: There is a building of 100 floors.If an egg drops from the Nth floor or above it will break . If it's dropped from any floor below, it will not break.You're given 2 eggs.Find N, while minimizing the number of drops for the worst case.

5.In a desert, 3 men found a big 24l jar full of water.Since there is shortage of water, they decided to distribute the water among themselves such that they all have equal amounts of it. But they only have a 133l, a 5l and an 11l jar. How do they do it ?

6.Two Persons: One always speaks truth and other always false.You don't know who is what. You are new to the city, you are allowed to ask exactly one question to find out the direction(for e.g. south or north), what question would you ask?