Radha travelled for 60 minutes. This travel of 60 minutes can be divided into 6 equal intervals of 10 minutes each. In these 6 intervals, she travelled 10 km, 12 km, 14 km, 9 km, 5 km and 15 km. What is the average speed of Radha if only those intervals are considered when her speed was between 50 km/hr and 80 km/hr?