You have two buckets each with a capacity of an integer number of units. The buckets have no measuring marks, and it is impossible to tell how much is in a partially-filled bucket by looking. You have to work out a way to measure out a certain integer number of units of water by pouring water into and out of the buckets.

The classic version of this puzzle is with a three-unit bucket and a five-unit bucket with the object of measuring out four units of water.

The three scenarios to solve are:

1) The two buckets have capacities of three units and seven units. Measure out two units.

2) Six and seven. Measure out four.

3) Five and eight. Measure out four.

Submit your answer to Gene Wirchenko <genew@telus.net>. Your answer should be in the form of a proof. That means to show how your answer must be correct. **The deadline is Wednesday, April 30, 2014 at noon Pacific Time.** I will post the answer shortly after.