Narayanrao was murdered by his palace guards in August 1773 and his which uncle became Peshwa ........

Explanation:

After the death of Madhavrao Peshwa in 1772, his brother Narayanrao became peshwa (ruler) of the Maratha Empire. Narayanrao was murdered by his palace guards in August 1773, and his uncle Raghunathrao (Raghoba) became peshwa. However, Narayanrao's widow, Gangabai, gave birth to a posthumous son, who was legal heir to the throne. The newborn infant was named 'Sawai' Madhavrao (Sawai means "One and a Quarter").