In one incident, a 15-year-old schoolgirl was allegedly raped by her classmate and a man, police said.
The girl, who had been missing from her house for the past three days, was found in a semi-conscious state near her house in Vikas Nagar, a suburb of Shimla last night.
"The girl has been hospitalised and a medical examination has been conducted," a police officer said.
The suspected rapist, who was a classmate of the victim and a minor, has been detained while his accomplice Hemraj, an adult, was arrested.
In another incident, a 16-year-old girl, who came from a village near Kufri to meet a relative at the Indira Gandhi Medical College and Hospital here, was raped by a taxi driver who had offered her a lift, police said.
The accused took the victim to a hotel where she was raped and left near the hospital this morning, police said.