User blog comment:Jademing/Oda is terrible at math/@comment-4783583-20120305211149

bakaaaaaaaaaaa

Roger's execution was 22 years ago, Brook knew about roger from 50 years ago.

50 - 22 = 28  (you obviously have to deduct the years that roger has been death from the years brook spent trapped in the florian triangle)

Meaning that 28 years before becoming the pirate king Roger was a rookie.

My guess is that Roger was about 47 years old when he died meaning that

47 -28 = 19

he was nineteen (luffy's current age) when he made a name for himself as a rookie.