A Texan is on his deathbed. He has but 1 8 litre barrel-full of petrol to his name. And he would so dearly share his posessions equally between his two sons. Trouble is, he lives in some remote corner of Texas by himself - sort of an anti-establishment figure. The only mesuring units he has at his disposal are 2 other empty barrels, one which could hold 5 litres and the other 3 litres. How does our idealist work that out? 

pour from the 8l into the 3l until full...(leaving 5 in the 8), then pour all from the 3 into the five. then fill the 3 again from the 8. now have 2 in the 8 3 in the 3 and 3 in the five. then use the 3 to fill up the 5. now have 2l in the 8 5l in the 5 and 1lin the 3. pour the entire 5l fromthe 5 into the 8, then put the 1l from the 3 into the 5. now have 7l in the 8, 1l in the 5 and 0 in the 3. then fill the 3 from the 8, and pour it into the 5l. now have 4l in the 8 and 4l in the 5. 0 in the 3.

He ask both sons to drive to visit him on the same day to collect their legacy. On the day they arrive he fills the 3ltr drum, and then pours this into the five ltr drum. He them refills the 3 ltr drum and pours this into the 5 ltr drum, but as the 5 ltr drum will be full at 5ltrs, the old man will have 1 ltr left over on the 3 ltr drum. He pours this one ltr into his eldest sons car. He the fills the 3 ltr drum and the 5 ltr drum abd pours this into his eldest sons car. He has now given his eldest son 9 ltrs, therefore he pours the remaining 9ltrs into his youngest sons car, and waves them goodbye know he has been fair and given both boys 9 ltrs each.

queenie....he only started with 8l, how is that he now has 9l for each which is 18l