And again

[chuckro]

This was inspired by Brian's comment on my last one. I'm just a puzzling machine. Please let me know, again, if you find more than one unique solution or a contradiction in my clues. Edit: Some minor corrections have been made based on comments.

This is the tale of six brothers: Arnold, Barry, Chester, David, Edward, and Frank. None of them are twins, and each of them has a whole-number age. What are the brothers' ages?

1. Frank is two years older than Barry.
2. Edward is half Chester's age.
3. David is two-thirds Arnold's age.
4. Half of the brothers can legally drink in the US.
5. None of the brothers has reached retirement age.
6. Two of the brothers' ages are prime numbers. Frank's age isn't one of them.
7. David was born between Edward and Barry.
8. Chester is the oldest, Arnold is second-oldest.
9. Barry is six years older than Edward.

Comments

[feiran.livejournal.com]

Chester is 28
Arnold is 24
Frank is 21
Barry is 19
David is 16
Edward is 13

The only thing that I found unclear about this one is the matter of a "round number." At first I thought you meant even numbers, or multiples of 5 or 10 depending on how you'd round them. That couldn't be right if numbers were supposed to be prime, so I gathered that you meant whole numbers, but you might want to state that outright.

[feiran.livejournal.com]

Sorry, typo: Chester is 26.