Music maestro Ustad Rashid Khan, who was undergoing treatment at a Kolkata-based hospital for prostate cancer, died at a Kolkata hospital this afternoon, officials said. The classical singer was 55. He is survived by his wife, two sons and a daughter. The classical singer, who belongs to the Rampur-Sahaswan Gharana, is the great-grandson of gharana founder Inayat Hussain Khan.