A 75-year-old man and a 35-year-old woman were arrested on prostitution-related charges in Roxbury Monday. Boston police said Nathan Andrews of Roxbury, who also goes by the name Fard Ahmed, was charging $20 for a two-hour room rental and selling condoms and alcohol at 131 Eustis St. He was charged with allowing a premise to be used for immoral purposes. Shannon-Lynn Quigley of Jamaica Plain was arrested on a charge of engaging in sex for a fee, police said. Another property owned by Andrews, which was suspected of being used for prostitution, was shut down by the city in August 2011 for code violations.Travis Andersen can be reached at email@example.com. Follow him on Twitter @TAGlobe.