A 23-year-old woman employee of a five-star hotel was killed, and her male colleague seriously injured after a speeding luxury car allegedly driven by a businessman’s son rammed into their motorcycle in North Goa, police said on Tuesday.The police on Monday arrested Darius Dias (22) in connection with the accident, which took place in the Dona Paula locality near here on Sunday night, an official said.Dias, who was allegedly driving a Mini Cooper, rammed the vehicle into the motorcycle, he said, adding that the car bore a temporary number plate, installed before a vehicle is registered with the Regional Transport Office (RTO).Diksha Parwadkar, who was riding pillion on the motorcycle, was declared dead on arrival at a private hospital, while her colleague D Arunkumar (26) remains in a critical condition, the official said.The duo was employed at a five-star hotel and were returning home after completing their night shift, he said, adding that a probe is under way.