In this task, you're given a passage, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.

Passage: In the 2007 NASCAR Craftsman Truck Series, Bires was the driver of the #21 Wood Brothers Racing truck in 19 races, handing over driving duties for the other six races to veteran Mark Martin. He had a tenth-place finish at Atlanta. After the departure of Jon Wood due to illness, Bires left the Truck Series and started racing for Tad Geschickter beginning at Nashville Superspeedway. His best Busch Series start was 26th and best finish was 7th in the Meijer 300 presented by Oreo race at Kentucky Speedway. Named the permanent driver of the #47 car in 2008, Bires had six top-ten finishes en route to a 13th-place points finish. But with Clorox/Kingsford moving up with Marcos Ambrose to the Sprint Cup Series, he was left without a full-time ride at the end of the season due to lack of sponsorship.
Link Information: Mark Anthony Martin (born January 9, 1959) is a retired American stock car racing driver. Question: At what age was Mark Martin the year that Kelly Bires handed over driving duties for the other six races to veteran Mark Martin?
Answer: 48