Here is the passage:
While teaching PTE, I came across the passage, and couldn't find green's relevant meaning.
Orville and Wilbur Wright were brothers living in Dayton, Ohio. The two had started making bicycles during the 1890s and had a successful small business selling their Wright Specials for $18 each ($475 in today’s green). This experience with building light, strong machines would prove valuable in the coming years after the brothers’ interest turned to flight.
My guess: it's today's currency notes in green color? Not sure though...