Math Riddles

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: In a certain society any time somebody commits a serious crime they must be shot at twice with a 6 bullet revolver. The revolver only has two bullets in it though, both of them right next to each other. They spin the revolver once and shoot the gun. If there was no bullet in that chamber they give the prisoner the option to either spin the chamber again or just shoot again. If the first shot is a blank, should the prisoner ask for the revolver to be spun or should they choose that it be shot again?

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

Question: You have an 8 by 8 chess board that has two corner squares diagonal from each other removed. Is there any way to place 31 dominoes of size 2x1 to cover the remaining 62 spaces?

Question: You have two coconuts and you want to find out how high they can be dropped from a 100 story building before they break. But you only have $1.40 and the elevator costs a dime each time you ride it up (it's free for rides down).

How can you drop the coconuts to guarantee you will find the lowest floor they will break at, while starting and ending at floor 1?

Note: They break when dropped from the same height and they don't weaken from getting dropped.