On a 360 km cycling route, three riders — P, Q, and R — start together. Initially, their speeds are 60 km/hr for Rider P, 50 km/hr for Rider Q, and 80 km/hr for Rider R. After the first 2 hours of riding, their speeds change as follows: Rider R reduces his speed to 80% of Rider P's original speed. Rider P adopts a new speed that is 25% higher than Rider R's speed at that moment. Rider Q increases his speed by 20% compared to his original speed. Find the time gap (in minutes) between the riders who finish first and second.